I don't think there's a standard abbreviation of "following" but we are used to using "ff." as the abbreviation of it.
The standard abbreviation is "assoc."
Decl. is the standard abbreviation for "declaration."
The standard abbreviation for height is ht.
No standard abbreviation
This abbreviation is Fr.
The standard abbreviation for Skopje is SK.
The standard abbreviation for California is CA.
The abbreviation for "Place" is Pl.
Decl. is the standard abbreviation for "declaration."
The abbreviation of weather is W.E.A.
The answer will depend on what ac is: it is not an abbreviation of any standard unit of length.The answer will depend on what ac is: it is not an abbreviation of any standard unit of length.The answer will depend on what ac is: it is not an abbreviation of any standard unit of length.The answer will depend on what ac is: it is not an abbreviation of any standard unit of length.
Yes it is. If you encounter the abbreviation "ff." in a text, it usually means "following", yes.