This is the 2701st most frequent Russian word.
белого
"Белого" means "of white" or "white" in the genitive case in Russian.
In this sentence, 'белого' is an adjective modifying 'краба', showing possession and description in accusative case.
Мы видели белого краба на пляже.
We saw a white crab on the beach.
Here 'белого' describes the noun 'вина' (wine), identifying its type and matching it in genitive case to indicate possession.
Ты помнишь вкус белого вина из Франции?
Do you remember the taste of white wine from France?
Here 'белого' denotes the color describing the book, acting as an adjective in genitive case.