What is "toe the line"

vb. 1 (context idiomatic English) To abide by the rules or conventions. 2 (context idiomatic English) To stand at one's mark before a footrace.

v. do what is expected

"Toe the line" is an idiomatic expression meaning either to conform to a rule or standard, or to stand poised at the starting line in a footrace. Other phrases which were once used in the early 1800s and have the same meaning were toe the mark and toe the plank.