Raised Back of Hand emoji is the human hand, raised up — it looks like the ✋ Raised Hand emoji reversed. As for the meanings, this emoji is commonly used as a symbol of the fact that the user agrees with something or supports something; in this sense, it serves as a symbol of voting. Also, it appears in every other meaning the ✋ Raised Hand gesture is used in real life. For example, it may mean that the user wants to attract attention, that they want to ask something or express their opinion. And at last, it is sometimes used in its direct meaning of a hand. (Source: Emojis.wiki, Fair use)