Antonyms of adj three-cornered

2 senses of three-cornered

Sense 1
three-cornered -- (having three corners; "a three-cornered hat")

INDIRECT (VIA angular) -> rounded -- (curving and somewhat round in shape rather than jagged; "low rounded hills"; "rounded shoulders")

Sense 2
three-cornered -- (involving a group or set of three; "a three-cornered race")

INDIRECT (VIA multilateral) -> unilateral, one-sided -- (involving only one part or side; "unilateral paralysis"; "a unilateral decision")

Similarity of adj three-cornered

2 senses of three-cornered

Sense 1
three-cornered -- (having three corners; "a three-cornered hat")
       => angular (vs. rounded), angulate -- (having angles or an angular shape)

Sense 2
three-cornered -- (involving a group or set of three; "a three-cornered race")
       => multilateral (vs. unilateral), many-sided -- (having many parts or sides)