x87

proper noun

An extension to the x86 CPU instruction set architecture, providing direct hardware support for advanced floating-point arithmetic operations (rather than requiring them to be emulated in software).

Meanings

proper noun
  1. computingAn extension to the x86 CPU instruction set architecture, providing direct hardware support for advanced floating-point arithmetic operations (rather than requiring them to be emulated in software).

Origin

Named after the product designations of the coprocessors used to provide floating-point support on early x86 systems lacking hardware support for these instructions in the main processor: the 8087 (for the 8086/8088 CPU), 80287 (for the 80286 CPU), 80387 (for the 80386 CPU), and 80487SX (for the 80486SX CPU). The 80486DX CPU and later integrated the floating-point hardware into the main processor, but the name continued in use for this set of instructions. The x serves as a wildcard.

Full word history & related roots →
Cite this entry
APA

x87. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/x87

MLA

“x87.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/x87. Accessed November 3, 2026.

Chicago

WatkinsX Dictionary, s.v. “x87,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/x87.

Source: x87 on Wiktionary, CC BY-SA 4.0.