To merge, to intermingle freely.
To form from different pieces or elements.
To bond pieces of metal into a continuous whole by liquefying parts of each piece, bringing the liquids into contact, and allowing the combined liquid to solidify.
To join into a single mass or whole.
To distinguish, make obvious the distinction between (two things) or of (something).
Used other than figuratively or idiomatically: to separate or isolate.
To select (something or someone) for a specific purpose.