CIF is Common Intermediate Format.  It is a format used to standardize the horizontal and vertical resolutions in pixels of video signals, commonly used in video teleconferencing systems.

Format Video Resolution
SQCIF 128 × 96
QCIF 176 × 144
CIF 352 × 288
4CIF 704 × 576
16CIF 1408 × 1152

D1 is Digital First.  It was the first major professional digital video format introduced in 1986 by the Society of Motion Picture and Television Engineers.  D-1 resolution is 720 × 480 for NTSC systems and 720 × 576 for PAL systems.  It is roughly 4 times higher than CIF in pixel resolutions. 

Mega-Pixels means the horizontal and vertical resolutions when multiplied produce a figure over 1,000,000.  For example High Definition TV is 1920 x 1080 (= Over 2,000,000 pixels) and is in the class of mega-pixels.