From WordNet (r) 2.0 (August 2003) [wn]:
guardian
adj : providing protective supervision; watching over or
safeguarding; "daycare that is educational and not just
custodial"; "a guardian angel"; "tutelary gods" [syn:
custodial, tutelary, tutelar]
n : a person who cares for persons or property [syn: defender,
protector, shielder]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Guardian \Guard"i*an\, n. [OF. guardain, gardien, F. gardien,
LL. guardianus. See Guard, v. t., and cf. Wasden.]
1. One who guards, preserves, or secures; one to whom any
person or thing is committed for protection, security, or
preservation from injury; a warden.
[1913 Webster]
2. (Law) One who has, or is entitled to, the custody of the
person or property of an infant, a minor without living
parents, or a person incapable of managing his own
affairs.
[1913 Webster]
Of the several species of guardians, the first are
guardians by nature. -- viz., the father and (in
some cases) the mother of the child. --Blackstone.
[1913 Webster]
Guardian ad litem(Law), a guardian appointed by a court of
justice to conduct a particular suit.
Guardians of the poor, the members of a board appointed or
elected to care for the relief of the poor within a
township, or district.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Guardian \Guard"i*an\ (g[aum]rd"[i^]*an or g[aum]rd"yan; 106),
a.
Performing, or appropriate to, the office of a protector; as,
a guardian care.
[1913 Webster]
Feast of Guardian Angels (R. C. Ch.) a church festival
instituted by Pope Paul V., and celebrated on October 2d.
Guardian angel.
(a) The particular spiritual being believed in some branches
of the Christian church to have guardianship and
protection of each human being from birth.
(b) Hence, a protector or defender in general. --O. W.
Holmes.
Guardian spirit, in the belief of many pagan nations, a
spirit, often of a deceased relative or friend, that
presides over the interests of a household, a city, or a
region.
[1913 Webster]