Subnormal and Tributary

Subnormal adjective - Of a size that is less than average.

Tributary and subnormal are semantically related. in lesser topic. In some cases you can use "Tributary" instead an adjective "Subnormal".

Tributary adjective - (of a stream) flowing into a larger stream.

Subnormal and tributary are semantically related. Sometimes you can use "Subnormal" instead an adjective "Tributary".