Antonyms of adj triangular

2 senses of triangular

Sense 1
triangular -- (having three angles; forming or shaped like a triangle; "a triangular figure"; "a triangular pyrimid has a triangle for a base")

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

Sense 2
trilateral, triangular, three-sided -- (having three sides; "a trilateral figure")

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

Similarity of adj triangular

2 senses of triangular

Sense 1
triangular -- (having three angles; forming or shaped like a triangle; "a triangular figure"; "a triangular pyrimid has a triangle for a base")
       => angular (vs. rounded), angulate -- (having angles or an angular shape)

Sense 2
trilateral, triangular, three-sided -- (having three sides; "a trilateral figure")
       => multilateral (vs. unilateral), many-sided -- (having many parts or sides)