Coalescence

[koh-uh-les] /ˌkoʊ əˈlɛs/

verb (used without object), coalesced, coalescing.
1.
to grow together or into one body:
The two lakes coalesced into one.
2.
to unite so as to form one mass, community, etc.:
The various groups coalesced into a crowd.
3.
to blend or come together:
Their ideas coalesced into one theory.
verb (used with object), coalesced, coalescing.
4.
to cause to unite in one body or mass.
/ˌkəʊəˈlɛs/
verb
1.
(intransitive) to unite or come together in one body or mass; merge; fuse; blend
v.

1540s, from Latin coalescere “to unite, grow together, become one in growth,” from com- “together” (see co-) + alescere “to grow up” (see adolescent). Related: Coalesced; coalescing; coalescence; coalescent.

coalescence co·a·les·cence (kō’ə-lěs’əns)
n.
See concrescence.