side by side adverb 3side-by-side adjective 1side-by-side noun 4forms 2 adverb3 •Beside or alongside one another; close to one another and abreast.The new houses were built side by side, facing the lake. •(figurative) With a common purpose.The soldiers of XX and YY were fighting side by side against a common enemy. •(figurative) In peace. side-by-side adjective1 •Adjacent; juxtaposed.The cylinder banks are at 60 deg. with the cylinders staggered to allow for side-by-side connecting rods on each crank. — 1958 side-by-side noun4 •A type of multipurpose off-highway utility vehicle, with four wheels, resembling a golf cart. •Ellipsis of side-by-side shotgun. •Ellipsis of side-by-side rifle. •Ellipsis of side-by-side smoothbore (“a side-by-side musket (unrifled) longarm”). formsside by sides · side-by-sides