Basin and Sag

Basin noun - A bowl-shaped vessel; usually used for holding food or liquids.

Sag and basin are semantically related in convex topic. In some cases you can use "Sag" instead a noun "Basin".

Sag noun - The extent to which something hangs or dips below a straight line.

Basin and sag are semantically related in drop topic. Sometimes you can use "Basin" instead a noun "Sag", if it concerns topics such as convex.