gratuity

1 a small sum of money given for a service over and above what is due for parties of eight or more, we automatically add a 15% gratuity onto the bill Synonyms tip, perquisiteRelated Words donation, gift, lagniappe, largesse (also largess), present; bonus, favor, reward; contribution, offering

2 something given in addition to what is ordinarily expected or owed got a $100 gratuity in addition to his regular pay Synonyms cumshaw, dividend, donative, extra, bonus, gravy, gravy train, lagniappe, perk, perquisite, throw-in, tipRelated Words pension; bestowal, presentation; benefaction, beneficence, benevolence, bounty, charity, generosity, largesse (also largess), philanthropy; contribution, donation, gift, offering, present; grant, subsidy; boon, manna, windfall; favor, freebie (or freebee), giveaway, premium; award, prize, reward; fringe benefit, icing