Definition of appreciation :
1. A just valuation or estimate of merit, worth, weight, etc.; recognition of excellence.
2. A rise in value; - opposed to depreciation.
3. Accurate perception; true estimation; as, an appreciation of the difficulties before us; an appreciation of colors.
sagacity, ecstasy, appreciativeness, intellect, clasp, hold, grip, leap, brownie points, thanks, time lag, sensitivity, upswing, estimation, cargo area, understanding, mouthful, spurt, acclaim, respect, discernment, clutch, rise, recognition, gustatory perception, compass, taste sensation, account, be glad of something, obligation, wait, delight, judgment, judgement, wisdom, kick, appreciative, perceptivity, range, cargo deck, gustatory modality, explosion, tasting, reason, sensitiveness, reach, satisfaction, affection, apprehension, grateful, wonder, storage area, excitement, sense of taste, enjoyment, handle, intelligence, intuition, detention, admiration, upsurge, credit, love, touch, keep, grasp, debt, clarity, taste, savvy, sensibility, postponement, clutches, commendation, vision, a pat on the back, perception, praise, jump, joie de vivre, clench, thankful, enthusiasm, wonderment, anticipation, consideration, honor, insight, gustatory sensation, surge, handgrip, compliment, indebted, pleasure, favor, detainment, brilliance, esteem, cargo hold, perceptiveness, gustation, penchant, custody, increase, percipience, regard, growth, taste perception, discretion, predilection, preference, common sense, sagaciousness, delay
gratitude (part of speech: noun)