Aperture: The opening in the lens through which light enters the camera.
Aspect Ratio: The width-to-height ratio of an image.
Auto Exposure Bracketing (AEB): Taking multiple photos with different exposures automatically.
Backlight: Light that comes from behind the subject.
Bit Depth: Number of bits used to represent each pixel.
Bokeh: The aesthetic quality of out-of-focus parts of an image.
Brightness: Overall lightness or darkness of an image.
Burst Mode: Taking multiple shots in quick succession.
Color Balance: The overall mix of colors in an image.
Color Space: The range of colors that can be represented in an image.
Compression: Reducing file size by removing data.
Contrast: The difference between the lightest and darkest areas of an image.
Crop Factor: The ratio of the dimensions of a camera's imaging area compared to a reference format.
Depth of Field (DOF): The distance between the nearest and farthest objects in focus in an image.
Digital Negative (DNG): An open lossless raw image format.
Digital Zoom: Enlarging a portion of an image digitally.
DPI (Dots Per Inch): Measurement of image resolution.
Dynamic Range: The ratio between the maximum and minimum measurable light intensities.
Exposure: Amount of light per unit area reaching the image sensor.
Exposure Bias: The adjustment of exposure set by the camera.
Exposure Compensation: A technique for adjusting the exposure indicated by a photographic exposure meter.
F-number: The ratio of the lens's focal length to the diameter of the entrance pupil.
Focal Length: The distance between the lens and the image sensor.
Flash: A burst of light from a camera to illuminate a scene.
Frame Rate: The frequency at which consecutive images are captured.
Gamma Correction: The process of altering the output intensity of light.
Histogram: A graphical representation of the tonal distribution in a digital image.
Hot Shoe: A mount on a camera to attach a flash unit.
Image Stabilization (IS): A family of techniques reducing blurring.
ISO Speed: The sensitivity of the camera's image sensor.
JPEG (Joint Photographic Experts Group): A commonly used method of lossy compression for digital images.
Light Meter: A device used to measure the amount of light.
Macro: Extreme close-up photography.
Manual Mode: A setting that lets the photographer control all the settings.
Megapixel: One million pixels.
Metering Mode: The way a camera determines exposure.
Noise: Random variation of brightness or color information in images.
Optical Zoom: Changing the focal length of a lens.
Overexposure: Receiving too much light, resulting in a too-bright image.
Panning: A technique where the camera is moved horizontally.
Pixel: The smallest controllable element of a picture represented on the screen.
RAW: A file format that contains minimally processed data from the image sensor.
Resolution: The detail an image holds.
Saturation: The intensity of color in an image.
Shutter Speed: The length of time when the film or digital sensor inside the camera is exposed to light.
Time Lapse: A photography technique where the frequency at which film frames are captured is much lower than that used to view the sequence.
Vignette: A reduction of an image's brightness or saturation at the periphery compared to the image center.
White Balance: A camera setting that adjusts for color temperature.
Zoom: A function that changes the focal length of the lens.

Exif-specific terms:

Exif Version: The version of Exif standard used to record the data.
FlashPix Version: The supported Flashpix version.
Color Space Information: The color space information tag (sRGB).
Image Description: Image title by user.
Make: Camera manufacturer's name.
Model: Camera model.
Orientation: The image orientation viewed with a viewer.
X Resolution: The number of pixels per ResolutionUnit in the ImageWidth direction.
Y Resolution: The number of pixels per ResolutionUnit in the ImageHeight direction.
Resolution Unit: The unit for measuring XResolution and YResolution.
Software: The software used for image processing.
Date and Time: The date and time when the original image data was generated.
Artist: The name of the camera owner, photographer or image creator.
YCbCr Positioning: The position of chrominance components relative to luminance components.
Copyright: The copyright information.
Exposure Time: The exposure time, given in seconds.
F Number: The F number.
Exposure Program: The class of the program used by the camera to set exposure when the picture is taken.
Spectral Sensitivity: The spectral sensitivity of each channel of the camera used.
Photographic Sensitivity (ISO): The ISO speed and ISO latitude of the camera or input device as specified in ISO 12232.
Opto-Electric Conversion Function (OECF): The Opto-Electric Conversion Function as specified in ISO 14524.
Sensitivity Type: The SensitivityType and standard output sensitivity values.
Standard Output Sensitivity: The standard output sensitivity value of a camera or input device defined in ISO 12232.
Recommended Exposure Index: The recommended exposure index value of a camera or input device defined in ISO 12232.
Date and Time (Original): The date and time when the original image data was generated.
Date and Time (Digitized): The date and time when the image was stored as digital data.
Shutter Speed Value: Shutter speed. The unit is the APEX (Additive System of Photographic Exposure) setting.
Aperture Value: The aperture value. The unit is the APEX value.
Brightness Value: The value of brightness. The unit is the APEX value.
Exposure Bias Value: The exposure bias. The unit is the APEX value.
Max Aperture Value: The smallest F number of the lens. The unit is the APEX value.
Subject Distance: The distance to the subject, given in meters.
Metering Mode: The metering mode.
Light Source: The kind of light source.
Flash: This tag is recorded when an image is taken using a strobe light (flash).
Focal Length: The actual focal length of the lens, in mm.
Maker Note: Manufacturer notes.
User Comment: Keywords or comments on the image; other than those in ImageDescription.
SubSecTime: A tag used to record fractions of seconds for the DateTime tag.
SubSecTimeOriginal: A tag used to record fractions of seconds for the DateTimeOriginal tag.
SubSecTimeDigitized: A tag used to record fractions of seconds for the DateTimeDigitized tag.
Flash Energy: Indicates the strobe energy at the time the image is captured, as measured in Beam Candle Power Seconds (BCPS).
Focal Plane X Resolution: Indicates the number of pixels in the image width (X) direction per FocalPlaneResolutionUnit on the camera focal plane.
Focal Plane Y Resolution: Indicates the number of pixels in the image height (Y) direction per FocalPlaneResolutionUnit on the camera focal plane.
Focal Plane Resolution Unit: Indicates the unit for measuring FocalPlaneXResolution and FocalPlaneYResolution.
Subject Location: Indicates the location of the main subject in the scene.
Exposure Index: Indicates the exposure index selected on the camera or input device at the time the image is captured.
Sensing Method: Indicates the image sensor type on the camera or input device.
File Source: Indicates the image source.
Scene Type: Indicates the type of scene.
CFA Pattern: Indicates the color filter array (CFA) geometric pattern of the image sensor when a one-chip color area sensor is used.

LeoUnderstanding EXIF Data: A Comprehensive Guide to 100 Terms and Jargons in Photography Metadata