co·a·lesce 
/ˌkowəˈlɛs/ verb
co·a·lesc·es; co·a·lesced; co·a·lesc·ing /ˌkowəˈlɛs/ verb [no obj] formal : to come together to form one group or mass
▪ a group of young reformers who gradually coalesced into a political movement ▪ The ice masses coalesced into a glacier over time.
▪ a group of young reformers who gradually coalesced into a political movement ▪ The ice masses coalesced into a glacier over time.
— co·ales·cence /ˌkowəˈlɛsn̩s/ noun
[noncount] ▪ a glacier formed by coalescence of ice masses [singular] ▪ a coalescence of forces
[noncount] ▪ a glacier formed by coalescence of ice masses [singular] ▪ a coalescence of forces
