  We use the orbifold approach to study theta functions in intrinsic mirror
symmetry. We introduce a new type of orbifold invariants for snc pairs, called
mid-age invariants, and use these invariants to define orbifold invariants
associated with the broken line type. Then, we define the orbifold theta
functions as generating functions of orbifold invariants with mid-ages. We show
that these orbifold theta functions are well-defined and satisfy the
multiplication rule.
