- to unite formally, as by treaty, league, marriage, or the like (usually followed by with or to): Russia allied itself to France.
- to associate or connect by some mutual relationship, as resemblance or friendship.
- a person, group, or nation that is associated with another or others for some common cause or purpose: Canada and the United States were allies in World War II.
- a plant, animal, or other organism bearing an evolutionary relationship to another, often as a member of the same family: The squash is an ally of the watermelon.
- a person who associates or cooperates with another; supporter.
- a person who advocates for or supports a marginalized or politicized group but is not a member of the group: Straight allies speak up for the LGBTQ community.As a man, how can I be a good ally to women in the struggle for gender equality?
- an adverbial suffix attached to certain adjectives with stems in -ic that have no forms ending in -ical: terrifically.
- to unite or be united, esp formally, as by treaty, confederation, or marriage
- to connect or be related, as through being similar or compatible
- a country, person, or group allied with another
- a plant, animal, substance, etc, closely related to another in characteristics or form