"change of substance, conversion of one substance into another," 1570s, originally in rhetoric, from Late Latin metastasis "transition," from Greek metastasis "a removing, removal; migration; a changing; change, revolution," from methistanai "to remove, change," from meta, here indicating "change" (see meta-) + histanai "to place, cause to stand," from PIE root *sta- "to stand, make or be firm." A rhetorical term in Late Latin for "a sudden transition in subjects," medical use for "shift of disease from one part of the body to another" dates from 1660s in English. Related: Metastatic.
1768, "penitence, spiritual conversion," from Greek metanoia "afterthought, repentance," from metanoein "to change one's mind or purpose," from meta, here indicating "change" (see meta-) + noein "to have mental perception," from noos "mind, thought," which is of uncertain origin.
late 14c., from Latin transfigurationem (nominative transfiguratio) "a change of form," noun of action from past-participle stem of transfigurare ""change the shape of" (see transfigure). In English, originally "the change in appearance of Christ before his disciples" (Matthew xvii.2; Mark ix.2, 3). The non-Christian sense is first recorded 1540s.
1896, "science or process of making images of objects on a sensitive plate by means of x-rays," from radiograph, the word for such an image-making device; from radio-, combining form of radiation, + -graph. Radiograph was used earlier as "device to measure and record the intensity of sunshine" (1880).