noun

1. A bounding straight edge of a two-dimensional shape.

   “A square has four sides.”

2. A flat surface of a three-dimensional object; a face.

   “A cube has six sides.”

3. One half (left or right, top or bottom, front or back, etc.) of something or someone.

   “Which side of the tray shall I put it on?  The patient was bleeding on the right side.”

Synonyms: edge, face, half, team, page, channel, station

verb

1. To ally oneself, be in an alliance, usually with "with" or rarely "in with"

   “Which will you side with, good or evil?”

2. To lean on one side.

3. To be or stand at the side of; to be on the side toward.

Synonyms: take side

adjective

1. Being on the left or right, or toward the left or right; lateral.

2. Indirect; oblique; incidental.

   “a side issue; a side view or remark”