1640s, "vindicatory, containing a defense," from French apologétique, from Latin apologeticus, from Greek apologetikos "defensible," from apologeisthai "speak in one's defense," from apologos "an account, story," from apo "away from, off" (see apo-) + logos "speech," from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')." Meaning "regretfully acknowledging failure" is by 1836 (apologetic for himself).
1660s, "long speech by one person, scene in a drama in which a person speaks by himself," from French monologue, from Late Greek monologos "speaking alone or to oneself," from Greek monos "single, alone" (from PIE root *men- (4) "small, isolated") + logos "speech, word," from legein "to speak," from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')." Related: Monologist.
1951, system of beliefs founded by L. Ron Hubbard; a hybrid word coined by him. In the book "Scientology: 8-80" (1952, The Hubbard Association of Scientologists Inc.) Hubbard described his thinking in coining the word:
"Scientology" is a new word which names a new science. It is formed from the Latin word, "scio", which means KNOW, or DISTINGUISH, being related to the word "scindo", which means CLEAVE. (Thus, the idea of differentiation is strongly implied.) It is formed from the Greek word "logos", which means THE WORD or OUTWARD FORM BY WHICH THE INWARD THOUGHT IS EXPRESSED AND MADE KNOWN: also, THE INWARD THOUGHT or REASON ITSELF. Thus, SCIENTOLOGY means KNOWING ABOUT KNOWING, or SCIENCE OF KNOWLEDGE.
The elements of it are Latin scire "to know" (for which see science) and Greek logos "word, speech, statement, discourse," also "computation, account," also "reason," from PIE *log-o-, suffixed form of root *leg- (1) "to collect, gather," with derivatives meaning "to speak," on notion of "to pick out words." There was a German scientologie (A. Nordenholz, 1937).
"eulogy, laudation, praise bestowed upon some person, action, or character," c. 1600, from French panégyrique (1510s), from Latin panegyricus "public eulogy," originally an adjective, "for a public festival," from Greek panēgyrikos (logos) "(a speech) given in or addressed to a public assembly," from panēgyris "public assembly (especially in honor of a god)," from pan- "all" (see pan-) + agyris "place of assembly," Aeolic form of agora (see agora). Related: Panegyrical; panegyrist.
early 14c., prologe, "introduction to a narrative or discourse," from Old French prologue (12c.) and directly from Latin prologus, from Greek prologos "preface to a play, speaker of a prologue," etymologically "a speech beforehand," from pro "before" (see pro-) + logos "discourse, speech," from legein "to speak," from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')." Especially a discourse or poem spoken before a dramatic performance or play. Figuratively, "a preliminary act or event," by 1590s.
A mathematical term given a wider sense by Plato. Meaning "partial agreement, likeness or proportion between things" is from 1540s. In logic, "an argument from the similarity of things in some ways inferring their similarity in others," c. 1600.
"repetition of the same word, or use of several words conveying the same idea, in the same immediate context; repetition of the same thing in different words; the useless repetition of the same idea or meaning," 1570s, from Late Latin tautologia "representation of the same thing in other words," from Greek tautologia, from tautologos "repeating what has been said," from tauto "the same" (contraction of to auto, with to "the" + auto, see auto-) + -logos "saying," related to legein "to say," from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')." Related: Tautological.
mid-14c., "the science of religion, study of God and his relationship to humanity," from Old French theologie "philosophical study of Christian doctrine; Scripture" (14c.), from Latin theologia, from Greek theologia "an account of the gods," from theologos "one discoursing on the gods," from theos "god" (from PIE root *dhes-, forming words for religious concepts) + -logos "treating of" (see -logy). Meaning "a particular system of theology" is from 1660s.
Theology moves back and forth between two poles, the eternal truth of its foundations and the temporal situation in which the eternal truth must be received. [Paul Tillich, "Systematic Theology," 1951]