coalesce

Etymology

From Latin coalēscō, from co- + alēscō (“grow up”).

verb

1. (of separate elements) To join into a single mass or whole.
   The droplets coalesced into a puddle.
   ... when a thing's own light and the light from something else coalescing into one on bright and smooth surfaces produce a form which yields a perception reversed from the way a thing normally looks. 2005, Plato, translated by Lesley Brown and 2, Sophist
2. (of a whole or a unit) To form from different pieces or elements.
   The puddle coalesced from the droplets as they ran together.
3. (engineering) 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.
4. (of separate groups or persons) To merge, to intermingle freely.