List of Latin phrases beginning with I

Common phrases and translations

• ibidem — "in the same place"; used in citations (abbreviated ibid.).
• idem — "the same"; used to indicate the same author or item in references.
• id est (i.e.) — "that is" or "that is to say"; used to restate or clarify.
• in absentia — "in absence"; used in legal and ceremonial contexts (trials, awards).
• in camera — "in a chamber"; denotes private judicial proceedings.
• in flagrante delicto — "while the crime is blazing"; used to describe being caught in the act.
• in loco parentis — "in the place of a parent"; used in education and guardianship contexts.
• in memoriam — "in memory of"; used on monuments and in dedications.
• in medias res — "into the middle of things"; a narrative technique that begins in the midst of action.
• in situ — "in its original position"; widely used in archaeology, geology, and biology.
• in vivo / in vitro — "within the living" / "in glass"; standard contrasts in biological research.
• ipse dixit — "he himself said it"; used to describe an assertion made without proof.

History and development

These phrases largely come from Classical and Medieval Latin and entered other languages through scholarly, legal, and ecclesiastical use. The Roman educational system and later medieval scholarship preserved many formulaic expressions that became fixed technical terms. Some Latin locutions have Greek antecedents in rhetoric, though their modern forms are Latin.

Uses, distinctions and notable facts

Many "I" phrases are technical: courts use in camera and in absentia, scientists contrast in vivo with in vitro, and scholars rely on ibidem, idem, and id est for concise citations and clarification. Others appear in literature or everyday speech (in medias res, in memoriam). Some are abbreviated (i.e., ibid., i.e.) and their punctuation and usage can differ between style guides.

Further reading

For general translations and reading lists see English translations and Latin phrase lists. For grammar and classical usage consult Latin language resources and discussions of earlier Greek influence at Greek rhetoric. Background on Roman literature and medieval transmission is available via Roman literature. For the complete index of phrases see the main compilation: List of Latin phrases.