Passing through or lying on the same straight line.(adjective)
Containing a common line; coaxial.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "collinear" in a sentence
"One is the data set might be too small -- what econometricians call "collinear" -- and the other is that the assumptions that you need are not really credible."
"No, not Newt's law, but Newton's Law, which says "The mutual forces of action and reaction between two bodies are equal, opposite and collinear.""
"However, I do though question your assumption that CO2 and Solar are collinear."