As

Syntax:
DIM Var AS TypeName
Member As TypeName
SUB Foo(Argument AS TypeName)
FUNCTION Foo AS TypeName

Keyword As precedes type name in declaration of variables, formal arguments, type members as function return values. It is not an operator or a statement, it is merely part of the syntax which make Lemick grammar easier to parse and read.

See also: Dim (1.3.12), Class (1.3.7), Sub (1.3.51), Function (1.3.24)