This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Moving in, consisting of, bounded by, or characterized by a straight line or lines: following a rectilinear path; rectilinear patterns in wallpaper.

adj. In a straight line.

adj. Formed from straight lines.

Straight-lined; bounded by straight lines; consisting of a straight line or of straight lines; straight: as, a rectilinear figure or course. Also rectilineal.

adj. characterized by a straight line or lines

"The lens used for this purpose must be capable of giving a perfectly sharp picture right up to the edges, and must be of the class called rectilinear, i.e., giving straight lines."

linear    one-dimensional   

rectilinear lens    rectilinear muscle   

rectangular    rectangle   

straight   

equilateral    four-sided    torsional    uncorruptible    straight-line    court    mud-walled    octahedral    luminiferous    etheric