This paper reports data from 17 adult and 141 child Hebrew-speakers from experiments testing knowledge of the semantics and pragmatics of coordination, using a variant of the Truth-Value Judgment Task (Crain & Thornton 1998). Adults showed uniformity in judgments of semantic meaning, the truth-conditions of conjunction (ve/’and’, aval/’but’) and disjunction (o/’or’) and the non truth-conditional contrast associated with aval/’but’. By contrast, judgments of the pragmatic meanings, the scalar quantity implicatures associated with the use of disjunction, and the pseudo-scalar quantity implicature associated with the use of aval/’but’ implicatures, varied. Children from the age of 5 showed uniform adultlike knowledge of semantic, truth-conditional meaning, while the non-truth-conditional semantic and pragmatic meanings were not demonstrated even at the age of 9;6. It is argued that it is uniformity which distinguishes semantics from pragmatics for adults. For children, it has been argued that earlier acquisition distinguishes semantics from pragmatics (e.g. Hyams 1996). It is argued that the distinction between semantic and pragmatic meanings in age of acquisition is a reflection of the relational complexity of these meanings, for instance as measured by Halford, Wilson & Philllips’ (1998) relational complexity metric, and is not related to their classification as semantic or pragmatic meaning.