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

1) To bend or be bent.
2) Of a material, to be capable of warping or bending and then reverting to shape (OxfordDictionaries.com).

Probably a back-formation from → flexible, from L. flexus, p.p. of flectere "to bend, turn."

Caftidan, caftan "to bend, incline," cafté "curved, bent," of unknown origin.

1) The quality of bending easily without breaking.
2) The ability to be easily modified.

→ flexible; → -ity.

Capable of being bent easily without breaking.

→ flex + -ible, variant of → -able.

1) The act of bending, the state of being bent.
2) The position that a limb assumes when it is bent.

→ flex; → -tion.

The action of bending or curving, or the condition of being bent or curved.

→ flex + suffix -ure.

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.