Synonyms

рука hand
NB Рука "hand" vs. кисть "hand." The word кисть is somewhat technical (i.e., anatomical) in style and less common than the word рука. Кисть suggests the bones rather than the flesh, and is used only with modifiers that describe visible properties. Thus, such adjectives as влажная "damp," горячая "hot," ловкая "nimble," can only be used with рука, but not with кисть. Certain verb phrases which may include рука are not allowed with кисть: потирать руки "to rub one's hands," взять в руку "to take in one's hand," держать в руке "to hold in one's hand," etc. Compare взять за руку "to take someone by the hand," which is a very common expression, and взять за кисть, which is almost a technical description of the same movement, appropriate for a doctor looking for pulse, or a coach showing a specific movement, etc.
кисти рукg (plural only) hands
NB Note that the expression кисти рук is very commonly used, unlike such expressions as пятки ног "heel." One may therefore consider it to be synonymous with кисть.
Кисти рук у Пети были худые, тонкие. Petya's hands were lean and slight.