COURTESY (O. Fr. curtesie, later courtoisie)  , manners or behaviour that suit a court, politeness, due consideration for others . A special application of the word is in the expression " by courtesy," where something is granted out of favour and not of right, hence " courtesy " titles, i.e. those titles of rank which are given by custom to the eldest sons of dukes, marquesses and earls, usually the second title held by the father; to the younger sons and to the daughters of dukes and marquesses, viz. the prefix " lord " and " lady " with the Christian and surname . For " tenure by the courtesy" see CURTESY . Another form of the word, " curtsey " or " curtsy," was early confined to the expression of courtesy or respect by a gesture or bow, now only of the reverence made by a woman, consisting in a bending of the knees accompanied by a lowering of the body .