Yes. It can mean to call to. Suratun-Nur Ayah 63 means, “Do not make du^a’ (call) to the Prophet as one of you makes du^a’ (call) to another.”
10- Can du^a’ be defined as anything other than worship?
Yes. It can mean to call to. Suratun-Nur Ayah 63 means, “Do not make du^a’ (call) to the Prophet as one of you makes du^a’ (call) to another.”