Rks
rks is a three-letter consonant cluster that appears in English orthography as a consecutive sequence of the letters r, k, and s. It occurs in many common words, particularly at the end of syllables or words, such as works, jerks, forks, larks, marks, sharks, and quirks.
In pronunciation, the rks cluster is typically realized as a postvocalic r plus a velar k followed
Orthographically, rks most often arises when a root ends in -rk and an inflection or plural -s
Rks is not a standalone word or a widely recognized abbreviation; rather, it is a common orthographic