Strong's Greek #3684 - ὀνικός, ή, όν onikos (of or for a donkey)

of or for a donkey

From onos; belonging to a ass, i.e. Large (so as to be turned by a ass) -- millstone.

see GREEK onos

Strong's 3684: ὀνικός

ὀνικός, ὀνικη, ὀνικον (ὄνος), of or for an ass: μύλος ὀνικός i. e. turned by an ass (see μύλος, 1), Mark 9:42 L T Tr WH; Luke 17:2 Rec.; Matthew 18:6. Not found elsewhere.

Strong's Greek: 3684. ὀνικός (onikos) — 2 Occurrences

Matthew 18:6 - Adj-NMS
GRK: κρεμασθῇ μύλος ὀνικὸς περὶ τὸν
NAS: it would be better for him to have a heavy millstone
INT: should be hung a millstone heavy upon the

Mark 9:42 - Adj-NMS
GRK: περίκειται μύλος ὀνικὸς περὶ τὸν
NAS: for him if, with a heavy millstone
INT: is put a millstone heavy about the