Main Entry:

¹com·ple·ment

Pronunciation:

\ˈkäm-plə-mənt\

Function:

noun

Etymology:

Middle English, from Latin complementum, from complēre to fill up, complete, from com- + plēre to fill — more at full

Date:

14th century

1 a: something that fills up, completes, or makes perfect b: the quantity, number, or assortment required to make a thing complete <the usual complement of eyes and ears — Francis Parkman> ; especially : the whole force or personnel of a ship c: one of two mutually completing parts : counterpart2 a: the angle or arc that when added to a given angle or arc equals a right angle in measure b: the set of all elements that do not belong to a given set and are contained in a particular mathematical set containing the given set c: a number that when added to another number of the same sign yields zero if the significant digit farthest to the left is discarded —used especially in assembly language programming3: the musical interval required with a given interval to complete the octave4: an added word or expression by which a predication is made complete (as president in “they elected him president” and beautiful in “he thought her beautiful”)5: the thermolabile group of proteins in normal blood serum and plasma that in combination with antibodies causes the destruction especially of particulate antigens (as bacteria and foreign blood corpuscles)

[complement illustration]