# STI

Source: https://englishreference.com/word/sti
Updated: 2026-08-27

## Senses

### 1. medical infection

noun · CEFR B2 · Technical

Stands for sexually transmitted infection. This is an illness you can get by having sex with someone who is already infected.

For teachers: Abbreviation for sexually transmitted infection. A clinical term for a pathogen passed between partners during sexual contact; it is often preferred over 'STD' in modern medical contexts to include asymptomatic cases.

- Using protection is the best way to prevent getting an STI.
- Public health clinics offer confidential testing for every common STI, emphasizing that early detection is crucial for effective treatment and preventing further transmission.

Usage: Usually used as a countable noun, often appearing in the plural form 'STIs'.

Teaching tip: Explain to students that STI has largely replaced STD (sexually transmitted disease) in professional and educational settings because many of these conditions do not show symptoms immediately.

## Examples

- Regular testing for an STI is part of good healthcare.
- Public health clinics provide free screenings and education to help prevent the spread of any common STI.
- While many people use the terms interchangeably, an STI refers to the presence of the pathogen in the body, whereas an STD describes the resulting disease state with visible symptoms.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.