pre-

The prefix 'pre-' is a Latin-derived element indicating anteriority in time or position: 'before' in‍​‌​‌​‌​‍​‌​‌​‍​‍​‍​‍​‍​‍​‌​‌​‌​‍​‍​‌​‌​‌​‌​‍​‍​‌​‍​‍​‌​‌​‍​‍​‍ time (previous, prehistoric), 'in front of' in space (preface, prefix), and 'preparatory' or 'preceding' more abstractly (prelude, preview). It descends from Latin 'prae' (before, in front of), itself from Proto-Indo-European *preh₂i or *prei-, a locative form of the deep directional root *per- meaning 'forward, through, in front.' The same PIE root produced Latin 'pro-,' Greek 'pro-' (πρό), Sanskrit 'pra-,' and English native 'fore-.'

In Latin, 'prae-' was productive in both nominal and verbal compounds. Verbs: 'praecedere' (to go before — whence 'precede'), 'praedicere' (to say beforehand — whence 'predict'), 'praeparare' (to make ready beforehand — whence 'prepare'), 'praeservare' (to keep safe from — whence 'preserve'). Nouns and adjectives: 'praefectus' (placed in charge — whence 'prefect'), 'praesidium' (garrison, protection — whence 'preside'), 'praeteritus' (gone by, past — whence 'preterite').

In Old French, Latin 'prae-' was regularly simplified to 'pre-,' and most English borrowings reflect this French-derived form rather than the classical Latin spelling. Through Middle English (c. 1200–1500) hundreds of 'pre-' words entered English: 'precede,' 'preach,' 'precious,' 'prefer,' 'prefix,' 'pregnant,' 'prejudice,' 'preliminary,' 'premise,' 'prepare,' 'present,' 'preserve,' 'preside,' 'pressure,' 'presume,' 'pretend,' 'prevent,' 'previous.' In many of these the prefix is not analysable to English speakers because both the prefix and the base arrived together and the base does not exist independently in English.

In Early Modern English (c. 1500–1700) 'pre-' became a productive prefix that could attach to English words freely. Renaissance scholars coined many 'pre-' words directly from Latin or as new compounds, and by the eighteenth century 'pre-' was fully naturalised as a live English prefix. The twentieth century saw a great expansion of productive 'pre-' formations: 'prefabricate,' 'predetermine,' 'preexist,' 'preheat,' 'preinstall,' 'pre-order,' 'pre-owned,' 'preschool,' 'preseason,' 'preview,' 'pre-workout,' 'pre-med,' 'pre-law.'

Hyphenation practice with 'pre-' varies. When the prefix is transparent and the base is an ordinary English word, hyphens are often used, especially if the base begins with 'e' to avoid misreading: 'pre-election,' 'pre-existing,' 'pre-eminent,' 're-entry.' When the word is fully naturalised, no hyphen is used: 'preview,' 'preschool,' 'pretest,' 'predict.' Modern style guides tend to drop hyphens in common words but retain them for clarity in nonce coinages.

A semantic distinction worth noting: 'pre-' indicates 'before,' while 'pro-' (from Latin 'pro,' forward, for, instead of) indicates 'forward' or 'in favour of.' The two prefixes derive from the same PIE root but have specialised in different directions. 'Proceed' and 'precede' both mean 'go forward / go before,' but 'proceed' implies 'go forward in action' while 'precede' implies 'go before in sequence.' The difference is subtle and native speakers generally recognise it intuitively.

Latin 'pre-' is cognate with native English 'fore-' (as in 'forecast,' 'forego,' 'foresee,' 'foreword,' 'foretell,' 'forefinger'). Both descend from PIE *per-, but 'fore-' came into English directly through the Germanic line while 'pre-' came via the Italic line through Latin and French. This gives English a pair of synonymous prefixes of different prestige registers: 'fore-' feels native, informal, and earthy ('forecast,' 'foresight'), while 'pre-' feels learned, technical, and scientific ('prediction,' 'prescience'). Sometimes the two prefixes attach to the same root to produce near-synonyms: 'foretell' and 'predict' mean nearly the same thing.

Allomorphy with 'pre-' is minimal. The prefix does not generally assimilate to the following consonant, unlike Latin 'in-' or 'ad-.' Spelling remains 'pre-' before all consonants and vowels, with the vowel sometimes pronounced /prɪ/ (in fully naturalised words: 'precise,' 'predict,' 'prefer') or /priː/ (in transparent coinages: 'preview,' 'preheat,' 'prepackage').

The related Latin prefix 'prae-' was preserved in a few learned or zoological terms, especially in anatomy and botany, where it indicates 'in front of' or 'before' ('praemolar' is occasionally written for 'premolar,' 'praeputial' for 'preputial'), but modern spelling almost always uses 'pre-.' Classical Latin sometimes wrote 'prae-' even where the vowel was short, and the spelling 'prae-' still appears in some British medical and scientific Latin.

Representative 'pre-' words include: preach, precaution, precede, precious, precise, predecessor, predicament, predict, predominate, preface, prefect, prefer, prefix, pregnant, prejudge, prejudice, preliminary, prelude, premature, premeditate, premier, premise, premium, preoccupy, preparatory, prepare, prepay, prerequisite, prerogative, prescribe, prescription, present, preservation, preserve, preside, president, pressure, prestige, prestidigitation, presume, pretend, pretext, pretty (etymologically unrelated — Old English 'prættig'), prevail, prevent, preview, previous. Productive modern: pre-book, pre-built, pre-cooked, pre-dawn, pre-emptive, pre-existing, pre-game, pre-heat, pre-industrial, pre-launch, pre-loaded, pre-made, pre-med, pre-order, pre-owned, pre-packaged, pre-paid, pre-qualify, pre-register, pre-release, pre-school, pre-season, pre-shrunk, pre-test, pre-war, pre-wash.