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

1) A case or occurrence of anything.
2) An example put forth in proof or illustration (Dictionary.com).

M.E., from O.Fr. instance, from L. instantia "presence; earnestness, urgency," literally "a standing near," from instans, → instant.

Seté, from set, present stem of setâdan, variant of istâdan "to stand," → standard, + -é noun suffix.

1a) An → infinitesimal or very short space of time;  a → moment.
1b) The point of time now present or present with reference to some action or even.
2a) Succeeding without any interval of time; prompt;  → immediate.
2b) Occurring, done, or prepared with a minimal amount of time and effort; produced  rapidly and with little preparation (Dictionary.com).

M.E., from O.Fr. instant (adj.) "assiduous, at hand," from M.L. instans-, in classical L. "present, pressing, urgent," literally "standing near," pr.p. of instare "to urge, to stand near, be present," → insist.

1) Lahzé, from Ar. laHZat, laHZa "glance; moment."
2) Setand (variant of istandé), from setâdan, variant of istâdan "to stand," → instance.

1) Occurring, done, or completed in an instant.
2) Existing at or pertaining to a particular instant (Dictionary.com).

→ instant; → -an; → -eous.

The → acceleration of a particle at time t defined by a = lim Δv/Δt = dv/dt. It is the limiting value of Δv/Δt at time t as both Δv and Δt approach zero.

→ instantaneous; → acceleration.

The velocity of a particle at some one instant of time, or at some one point of its path. It can be defined as the limiting value of the average velocity when the second point is taken closer and closer to the first point.

→ instantaneous; → velocity.

The arched upper surface of the human foot between the toes and the ankle (Dictionary.com).

→ in-; → step.

Ruyé, → surface; pâ, → foot.

To provoke, urge, or incite.

From L. instigatus, p.p. of instigare "to urge on, incite," from → in- "in" + *stigare "to prick," from PIE root *steig- "to prick, stick, pierce," cognate with Pers. tig, tiz, → sharp.

Âqâlidan "to excite, rouse."

The act of instigating; incitement.

Verbal noun of → instigate.

1) An object used for producing music.
2) A measuring device designed to record the present value of a quantity under observation.

From O.Fr. instrument, from L. instrumentem "a tool, apparatus, furniture," from instruere "to arrange, furnish," from → in- + struc- (var. s. of struere "to put together") + -tus p.p. suffix.

1) Sâz "(musical) instrument; apparatus; harness; furniture," from sâzidan, sâxtan "to build, make, fashion; to adapt, adjust, be fit" (from Mid.Pers. sâxtan, sâz-, Manichean Parthian s'c'dn "to prepare, to form;" Av. sak- "to understand, to mark," sâcaya- (causative) "to teach").
2) Sâzâl, from sâz + -âl, → -al.

The correctable part of the inaccuracy of a measuring instrument.

→ instrument; → error.

Of, relating to, or performed by or with one or more instruments.
See also:
→ instrumental broadening, → instrumental flexure, → instrumental magnitude, → instrumental profile, → instrumental response function, → instrumentalism, → instrumentalist.

Adj. of → instrument.

The broadening of a point source caused by the response functions of the telescope and the instrument used.

→ instrumental; → broadening.

An image defect caused by the mechanical flexure of materials; for example the curved-shape image of a long slit in a spectrograph.

→ instrumental; → flexure.

The magnitude derived directly using → Pogson's relation. The instrumental magnitude depends on → detector→ sensitivity, telescope → aperture, exact filter → bandpass, etc. It must be → calibrated to some standard → photometric system.

→ instrumental; → magnitude.

The shape of instrument's response to the input signal. The Fourier transform of the source function by the instrument function.

→ instrumental; → profile.

The mathematical form of the way an instrument affects the input signal.

→ instrumental; → response; → function.

In the philosophy of science, the pragmatic view that a scientific theory is no more than a useful instrument or tool for getting our experiences in some order.

→ instrumental; → -ism.

An astronomer, engineer, or technician who is concerned with the construction of astronomical instruments.

→ instrumental + → -ist.

1) The design and use of scientific instruments for detection, measurement, control, computation, and so on.
2) The ensemble of instruments contained in a given machine or system.

From → instrument + -ation a combination of -ate and -ion, used to form verbal nouns.

Sâzâlgari, noun from sâzâlgar, → instrumentalist. Sâzâlgân, with plurality suffix -gân.

To cover or to separate from conducting bodies by means of nonconductors so as to prevent or reduce the passage, transfer, or leakage of heat, electricity, or sound. → insulation, → insulator.

From L. insulatus "made into an island," from L. insula "island."

From âyeq, → insulator, + kardan "to do," → -or.