Two words for working together are cooperate or collaborate.
teamwork
(Also: Collaboration, inter-working)
Collaborate.
Collaboration - work together
to work together.to gather up in a group
Cooperate.
Another word for grin teeth together would be grit.
Another word for work partner is colleague.
Work
in addition to,and,plus,with,together with
Together
A word meaning "to come together" is join.
Another word could be specialty or best work
alike together?
assemble