6 letters · 8 points in Scrabble
noun a positively charged ion
originLearned borrowing from Ancient Greek κᾰτῐόν (kătĭón), neuter present participle of κᾰ́τειμῐ (kắteimĭ, “to go down, come down”), from κᾰτᾰ- (kătă-, “downwards, down, cata-”) + εἶμῐ (eîmĭ, “to go, come”). Coined by English polymath William Whewell in 1834 for Michael Faraday, who introduced it later that year. By surface analysis, cat(a)- + ion.
Etymology from Wiktionary, CC BY-SA 3.0