I use the following simple formula to distinguish among symmetric/asymmetric encryption and hashing.
C = Enc (P, K1)
P = Dec (C, K2)
C is cypher text,
P is plain text,
Enc is an encryption algorithm,
Dec is an decryption algorithm,
K1 is a key for encryption.
K2 is a key for decryption.
If K1 == K2, then Enc and Dec are symmetric encryption (e.g., AES).
If K1 != K2, then Enc and Dec are asymmetric encryption (e.g., RSA).
If Enc is an one-way function (there is not a Dec to recover C to P), we can call it hashing (e.g., SHA).