イコール

Etymology
Borrowed from.

First cited to a text from 1901.

Adjective

 * 1)  equal, equivalent, the same

Noun

 * 1)  the equals sign, =

Particle

 * 1)   equals, is equal to, is equivalent to, entails

Usage notes
Usage of this term is unusual for Japanese grammar. This behaves in an attributive manner, coming immediately after a noun or noun phrase (with that noun phrase occasionally taking the subject particle ), and then modifying a following noun or noun phrase. However, the word ikōru does not belong to any of the classes of words that normally function attributively in Japanese: it is not a verb or adjective. Nor does this usage include the attributive particles or  after ikōru.

This construction appears to have developed from use of the term in mathematics, where equations are written and read much in the same manner as in English: 1 + 1 = 2, ichi purasu ichi ikōru ni.