1. toward one side

e.g. the car slipped sideways into the ditch
leaning sideways
a figure moving sidewise in the shadows

Synonym: sidewayssidewise

2. from the side
obliquely

e.g. a picture lit sideways
scenes viewed sidewise

Synonym: sidewayssidewise

3. with one side forward or to the front

e.g. turned sideways to show the profile
crabs seeming to walk sidewise

Synonym: sidewayssidewise