Old English fæder "he who begets a child, nearest male ancestor;" also "any lineal male ancestor; the Supreme Being," and by late Old English, "one who exercises parental care over another," from Proto-Germanic *fader (source also of Old Saxon fadar, Old Frisian feder, Dutch vader, Old Norse faðir, Old High German fatar, German vater; in Gothic usually expressed by atta), from PIE *pəter- "father" (source also of Sanskrit pitar-, Greek pater, Latin pater, Old Persian pita, Old Irish athir "father"), presumably from baby-speak sound "pa." The ending formerly was regarded as an agent-noun affix.
My heart leaps up when I behold
A rainbow in the sky:
So was it when my life began;
So is it now I am a man;
So be it when I shall grow old,
Or let me die!
The Child is father of the Man;
I could wish my days to be
Bound each to each by natural piety.
[Wordsworth, 1802]
The classic example of Grimm's Law, where PIE "p-" becomes Germanic "f-." Spelling with -th- (15c.) reflects widespread phonetic shift in Middle English that turned -der to -ther in many words, perhaps reinforced in this case by Old Norse forms; spelling caught up to pronunciation in 1500s (compare mother (n.), weather (n.), hither, gather). As a title of various Church dignitaries from c. 1300; meaning "creator, inventor, author" is from mid-14c.; that of "anything that gives rise to something else" is from late 14c. As a respectful title for an older man, recorded from 1550s. Father-figure is from 1954. Fathers "leading men, elders" is from 1580s.
mid-13c., mirour, "polished surface (of metal, coated glass, etc.) used to reflect images of objects," especially the face of a person, from Old French mireoir "a reflecting glass, looking glass; observation, model, example," earlier miradoir (11c.), from mirer "look at" (oneself in a mirror), "observe, watch, contemplate," from Vulgar Latin *mirare "to look at," variant of Latin mirari "to wonder at, admire" (see miracle).
The Spanish cognate, mirador (from mirar "to look, look at, behold"), has come to mean "watch tower, gallery commanding an extensive view." Latin speculum "mirror" (or its Medieval Latin variant speglum) is the source of words for "mirror" in neighboring languages: Italian specchio, Spanish espejo, Old High German spiegal, German Spiegel, Dutch spiegel, Danish spejl, Swedish spegel. An ancient Germanic group of words for "mirror" is represented by Gothic skuggwa, Old Norse skuggsja, Old High German scucar, which are related to Old English scua "shade, shadow."
Words for 'mirror' are mostly from verbs for 'look', with a few words for 'shadow' or other sources. The common use of the word for the material 'glass' in the sense of 'mirror' seems to be peculiar to English. [Carl Darling Buck, "A Dictionary of Selected Synonyms in the Principal Indo-European Languages," 1949]
Figurative use, "that in or by which anything is shown or exemplified," hence "a model (of good or virtuous conduct)" is attested from c. 1300. Mirrors have been used in divination since classical and biblical times, and according to folklorists, in modern England they are the subject of at least 14 known superstitions. Belief that breaking one brings bad luck is attested from 1777. Mirror image "something identical to another but having right and left reversed" is by 1864. Mirror ball attested from 1968. To look in (the) mirror in the figurative sense of "examine oneself" is by early 15c.