enlist

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To engage (persons or a person) for service in the armed forces.
2. v. To engage the support or cooperation of.
3. v. To enter the armed forces.
4. v. To participate actively in a cause or enterprise.

Century Dictionary and Cyclopedia

1. To enter, as a name on a list; enroll; register.
2. To engage for public service, especially military or naval service, by enrolling after mutual agreement: as, to enlist men for the army.
3. To unite firmly to a cause; employ in advancing some interest; engage the services of: as, to enlist one's sympathies in the cause of charity.
4. Synonyms and Enroll, etc. See record, v.
5. To engage in public service, especially military service, by subscribing articles or enrolling one's name; specifically, to engage in such service voluntarily.
6. To enter heartily into a cause, with devotion to its interests.

Wiktionary

1. v. intransitive To join a cause or organization, especially military service.
2. v. transitive To recruit the aid or membership of others.
3. v. To secure, to obtain.

GNU Webster's 1913

1. v. To enter on a list; to enroll; to register.
2. v. To engage for military or naval service, the name being entered on a list or register.
3. v. To secure the support and aid of; to employ in advancing interest.
4. v. To enroll and bind one's self for military or naval service
5. v. To enter heartily into a cause, as if enrolled.

WordNet 3.0

1. v. hire for work or assistance
2. v. engage somebody to enter the army
3. v. join the military