First link:
19. “Chereme” (Stokoe, 1960), is the technical term for the smallest meaningful units of sign language analysis, analogous to phonemes in oral languages. Derived from the Greek for “hand”, cheremes are classified into hand configurations, movements and places of articulation.

Second link:

Note A: A common misunderstanding is that phonemes are sounds. Actually a phoneme is a theoretical construct; no one has ever uttered a phoneme. "At first glance it might seem inappropriate to use terms based on sound-phoneme and phonology--to refer to soundless languages. The earliest work avoided the problem by coining the term chereme. By today it has been demonstrated conclusively though that these units are organizationally and functionally equivalent at every level of linguistic structure. The terminology refers to the pattern of organization of the linguistic signals rather than to the formal properties of the signals themselves.