Longman Dictionary of Contemporary English - alliance

~ W3 n 1 an arrangement in which two or more countries, groups etc agree to work together in order to try to change or achieve something + between  (The alliance between students and factory workers in the 1960s)  (Britain's military alliance with her Nato partners.) enter into/form an ~ (=agree to work together)  (The two countries entered into a defensive alliance.) 2 a group that is formed when two or more countries, groups etc work together 3 in ~ (with) if two groups, countries etc are in alliance, they work together to achieve something or protect one another  (Relief workers in alliance with local charities are trying to help the famine victims.) 4 formal close relationship, especially a marriage, between people  (- see also unholy ~ (unholy (3)))