IEEE Floating-Point Standard: Terminology
Significand: The portion of the binary floating-point number that consists of an explicit or implicit leading bit (0 or 1) to the immediate left of the radix point and a fraction to the right of the radix point.
Normal 0: Minimum exponent and 0 significand
Denormalized: Minimum exponent, implicit or explicit leading bit 0 but number is not a normal 0.
Unnormalized: Occurs in IEEE extended format
Normalized: Non-zero number where leftmost significant bit is a 1. Normalization does not change the sign of a number.
Special guard digits are used in rounding: