General: Limitation or restriction.
Mechanics: Any restriction imposed on the position or motion of a material system.
Constraints are said to be internal if they do not impede free displacement of the system.
All other kinds of constraints are called external. Systems subject only to
internal constraints are free material systems.
Physics: A fact or condition, usually observational, that allows to
reduce the number of free parameters in a theoretical model.
Etymology (EN): M.E. constreinte, from M.F., from constreindre, from
L. constringere “to bind together, tie tightly,” from
→ com- “together”
- stringere “to bind, draw tight.”
Etymology (PE): Pâvand “fetter, shackle,” from pâ “foot”
(Mid.Pers. pâd, pây; Khotanese fad; Av. pad-; cf. Skt. pat-,
Gk. pos, genitive podos; L. pes, genitive pedis;
P.Gmc. *fot, E. foot, Ger. Fuss, Fr. pied;
PIE *pod-/*ped-) + vand, variant band “tie, band,”
(Mod.-Mid./Pers. bastan/vastan “to bind, shut,”
Av./O.Pers. band-
“to bind, fetter,” banda- “band, tie,”
Skt. bandh- “to bind, tie, fasten,” PIE
*bhendh- “to bind,” cf. Ger. binden, E. bind).
