Ally \Al*ly"\, v. t. [imp. & p. p. {Allied}; p. pr. & vb. n.
{Allying}.] [OE. alien, OF. alier, F. alier, fr. L. alligare
to bind to; ad + ligare to bind. Cf. {Alligate}, {Alloy},
{Allay}, {Ligament}.]
1. To unite, or form a connection between, as between
families by marriage, or between princes and states by
treaty, league, or confederacy; -- often followed by to or
with.

O chief! in blood, and now in arms allied. --Pope.

2. To connect or form a relation between by similitude,
resemblance, friendship, or love.

These three did love each other dearly well,
And with so firm affection were allied. --Spenser.

The virtue nearest to our vice allied. --Pope.

Note: Ally is generally used in the passive form or
reflexively.