Grant, concede, allow are comparable when they mean to admit something in question, especially a point or contention of one’s opponent in an argument.
Grant usually implies voluntary acceptance in advance of proof in order to clarify the issues or to center attention on what are regarded as the main issues.
Concede implies reluctant acceptance either before or after proofs have been advanced; it usually suggests the strength of the opponent’s contention.
Allow implies acceptance, but usually a somewhat qualified acceptance; it often suggests admission on the ground of apparent truth, logical validity, or reasonableness.