engagement, eternity (esp. BrE), promise (esp. AmE), purity (esp. AmE), signet, wedding
diamond, gold, silver, etc.
She wore a diamond engagement ring.

belly-button, eyebrow, lip, navel, nipple, nose, tongue, etc.
She had a small nose ring.

pinky (AmE)
championship, Super Bowl™ (both AmE)
He has earned three Super Bowl rings in the last four years.

have on, sport, wear
He had a signet ring on his little finger.
His right ear sported a gold ring.

put on, slide on, slip on
He slipped the ring on her finger.

pull off, slide off, slip off, take off
exchange
They exchange rings and wedding vows.

kiss
She kissed the great ring of the archbishop of Chicago.

finger (= the finger next to the little finger, esp. on the left hand)
box (esp. AmE)
I pulled the small ring box out of my pocket.

inner, innermost
outer, outermost
concentric
The street plan of the city has evolved as a series of concentric rings.

black, dark
He had dark rings around his eyes.

smoke
He can blow smoke rings.

tree
onion
a plate of onion rings

teething
napkin

form, stand in
The children formed a ring around their teacher.

ring of
a ring of fire/smoke/stones

in a/the ring
The children sat on the floor in a ring.

boxing, bull, circus, show, wrestling

enter
He entered the ring wearing his usual outfit.

leave
Ashton left the ring with a nasty cut to the right eye.

in the ring, into the ring
He was back in the ring (= the boxing ring) only a month after the injury.

retire from the ring (= stop boxing)

drug (esp. AmE), drugs (BrE), money-laundering, prostitution, smuggling, spy

be involved in
break up, bust (esp. AmE)
Customs officials have broken up a major drug ring.

give sb
I'll give you a ring once I get home.