Additional; added to supply what is wanted.

Something additional; an extra.

plural of supplementary

The quality of being supplementary.

(geometry) plural of supplementary angle

(geometry) A pair of angles that sum to 180 degrees.

(geometry) An angle that, when added to another referenced angle, produces an angle of 180 degrees.

plural of supplementary plane

(computing) Any of the 16 Unicode planes located above Plane 0 (the BMP) and requiring the use of surrogate pairs to encode in UTF-16 (Planes 1 through 16, collectively covering the range of code points from U+10000 through U+10FFFF).

(computing, Unicode) Any character assigned a code point in one of the supplementary planes (planes 1 through 16, covering the range U+10000 through U+10FFFF).