An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

An axiom in → statics, stating that any → constrained body can be treated as a → free body detached from its → constraints, provided the latter are represented by their → reactions.

→ axiom; → constraint.

To confine forcibly, as by bonds; to force, compel, or oblige; to repress or restrain. → constrained body, → constrained system.

→ constraint.

A → rigid body whose displacement is prevented because it is under → constraint or a body that can move only in certain directions. Contrasted with → free body.

Constrained, p.p. of → constrain; → body.

Opposite of a → free system. See also → constraint.

Constrained, p.p. of → constrain; → system.

1) General: Limitation or restriction.
2) 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.
3) Physics: A fact or condition, usually observational, that allows to reduce the number of free parameters in a theoretical model.

M.E. constreinte, from M.F., from constreindre, from L. constringere "to bind together, tie tightly," from → com- "together" + stringere "to bind, draw tight."

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).

To hold back from action; keep in check; repress; to limit or hamper the activity, or effect of.

M.E. restreynen, from O.Fr. restreindre "press, push together; curb, bridle;" from L. restringere "to draw back tightly, confine," from → re- "back" + stringere "draw tight," → strain.

Bâzdâštan, from bâz- prefix denoting "reversal, opposition," → re-, + dâštan "to hold," → property.

Change of volume and/or shape of a body, or part of a body, due to an applied → stress. When a body is deformed by such a force, through compression or distension, the strain is the ratio of the dimensional change to the original or un-strained dimension. The strain may be a ratio of lengths, areas, or volumes. See also → shear.

M.E. streinen (v.), from O.Fr. estreindre "to bind tightly, clasp, squeeze," from L. stringere "to bind or draw tight," from PIE base *strenk- "tight, narrow; pull tight, twist;" cf. Gk. strangein "twist;" Lith. stregti "congeal;" O.H.G. strician "mends nets;" Ger. stramm, Du. stram "stiff."

Šepil "squeeze; fondness" (Dehxodâ) of unknown origin.