Luke 1:4κατηχήθης
so that you may know the certainty of the things you have been taught.
Acts 18:25κατηχημένος
He had been instructed in the way of the Lord and was fervent in spirit. He spoke and taught accurately about Jesus, though he knew only the baptism of John.
Romans 2:18κατηχούμενος
if you know His will and approve of what is superior because you are instructed by the law;
1 Corinthians 14:19κατηχήσω
But in the church, I would rather speak five coherent words to instruct others than ten thousand words in a tongue.
Galatians 6:6κατηχούμενος
Nevertheless, the one who receives instruction in the word must share in all good things with his instructor.

Abbott-Smith

κατ-ηχέω, -ῶ

1. to resound.

2. to teach by word of mouth, instruct, inform (see 131., Phil. Gosp., 20, 31): Gal.6:6; with accusative of person(s), 1Co.14:19; pass. with accusative of thing(s), Luk.1:4 (ICC, in l), Act.18:25 21:24 (cf. Lk, l.with), Gal.6:6; before κ, with genitive of thing(s), Rom.2:18; περί, with genitive of person(s), Act.21:21.†
(AS)

Sources: Abbott-Smith’s Manual Greek Lexicon of the New Testament (1922, public domain) and glosses from STEPBible TBESG (CC BY 4.0); STEPBible TAGNT (Greek New Testament, CC BY 4.0); the Berean Standard Bible (public domain). Reformatted by Word Study, wording unchanged. All sources and licenses.