Overview

To is one of the most frequent words in English, serving mainly as a preposition of direction or relation and as the marker that introduces the infinitive form of verbs. Its role changes with context: it can link nouns and pronouns to other parts of the sentence, or it can form verb phrases that express purpose, intention, or future action.

Forms and pronunciation

Written as to in lowercase within a sentence, it has two common pronunciations in modern English: the full form /tuː/ and a reduced weak form /tə/ (often transcribed [tə] or [tʊ]) used in unstressed positions. It is not contracted with an apostrophe and is capitalized only when required by sentence position or title conventions.

Primary grammatical functions

To performs two distinct grammatical jobs:

  • Preposition: Indicates direction, recipient, limit, purpose, or relation (e.g., "go to the store," "give this to her," "from five to seven"). As a preposition it takes a noun phrase as its complement.
  • Infinitive marker (particle): Introduces the bare infinitive of a verb to form constructions of purpose, intent, obligation, or future action (e.g., "to read," "to make amends"). As a particle it precedes a verb base form, not a noun phrase.

Examples and common uses

Examples illustrate typical contrasts: "I walked to the park" (preposition, direction) versus "I want to walk" (infinitive, verb complement). "To" appears in fixed expressions and ranges: "from A to B," "to and fro," and in addresses or correspondences as a header field label (To:).

History and cognates

The word comes from Old English tō and ultimately from a Proto‑Germanic ancestor meaning "to, toward." Cognates appear in other Germanic languages with similar directional particles. Over centuries its syntactic uses expanded in English to include the infinitive particle recognized today.

Notable distinctions and usage notes

  • Do not confuse to with the homophones too (meaning "also" or "excessively") and two (the numeral 2).
  • The so‑called "split infinitive" inserts words between to and a verb ("to boldly go"); many modern style guides accept this when it improves clarity or rhythm.
  • In title case style guides, to is commonly lowercased as a short preposition or infinitive particle unless rules specify otherwise.