closer

Etymology 1

adj

1. comparative form of close: more close
   In the spring of 1938 the Japanese imperialists invaded Yü-tz'u and T'ai-ku in Shansi. Everyone was in panic as the flames of war came closer and closer to Hsiang-yüan hsien. 1976, Sidney L. Greenblatt, editor, The People of Taihang, White Plains, NY: International Arts and Sciences Press, →LCCN, →OCLC, page 168
   [The researchers] noticed many of their pieces of [plastic marine] debris sported surface pits around two microns across. Such pits are about the size of a bacterial cell. Closer examination showed that some of these pits did, indeed, contain bacteria, […]. 2013-07-20, “Welcome to the plastisphere”, in The Economist, volume 408, number 8845

Etymology 2

From Middle English closere, equivalent to close (verb) + -er.

noun

1. Someone or something that closes.
   In our organization, the VP of Sales usually acts as the closer.
2. Someone or something that concludes.
   The DJ chose a fantastic track as his closer at the end of the night.
3. (sales) Synonym of close (“the point at the end of a sales pitch when the consumer is asked to buy”)
4. The last stone in a horizontal course, if smaller than the others; a piece of brick finishing a course.
   The longitudinal bond of the walls is only 24 inches, or one fourth of the length of a brick of 9 inches, and is obtained by introducing closers 24 inches broad 1852, Notes on Building and Road-making
5. (baseball) A relief pitcher who specializes in getting the last three outs of the game. See Wikipedia:closer (baseball)
   They brought their closer in for the ninth.