Int. Standard Bible Encyclopedia ACHAICUS a-ka'-i-kus (Achaikos, "belonging to Achaia"): A name honorably conferred upon L. Mummius, conqueror of Corinth and Achaia (compare CORINTH). Achaicus was one of the leaders of the Corinthian church (to be inferred from 1 Corinthians 16:15) who, visiting Paul at Ephesus with Stephanas and Fortunatus, greatly relieved the Apostle's anxiety for the Corinthian church (compare 1 Corinthians 5:1). Paul admonishes the members of the Cor church to submit to their authority (compare 1 Thessalonians 5:12) and to acknowledge their work (1 Corinthians 16:15).

Multi-Version Concordance Achaicus (1 Occurrence) 1 Corinthians 16:17 I rejoice at the coming of Stephanas, Fortunatus, and Achaicus; for that which was lacking on your part, they supplied. (WEB KJV WEY ASV BBE DBY WBS YLT NAS NIV)