Together or in collaboration:
• They worked _jointly_ on a research project.
• The two companies announced a _joint_ venture.
Shared or common:
• The tenants have _joint_ custody of the house.
• They filed a _joint_ tax return.
Connected or linked:
• The two pieces of wood were _jointly_ nailed together.
• The bones of the skeleton are held _jointly_ by ligaments and tendons.
Mutually or reciprocally:
• They are _jointly_ responsible for the debt.
• We made a _joint_ decision to go on a trip.
Simultaneously or in combination:
• The train arrived _jointly_ with the bus.
• The ingredients in the recipe create a _joint_ flavor.
With equal authority or responsibility:
• The project is led by two _joint_ managers.
• The decision was made _jointly_ by the board members.
Unified or combined:
• The two organizations _jointly_ form an alliance.
• The countries established a _joint_ task force to address the crisis.
When combined with other words, the meaning of "jointly" can change or become more specific. For example, "jointly and severally" is a legal term indicating that each party is individually responsible for the full obligation, while "joint ownership" refers to shared property ownership.