| API | Application Programming Interface | In English | → Software → Networks, communication |
| API | Air Position Indicator | In English | |
| API | Allocation de Parent Isolé | In French | → Social welfare |
| API | Autorisation(s) de Programme Individualisée(s) | In French | |
| API | Application Program Interface | In English | → Software → Networks, communication |
| API | Année Polaire Internationale | In French | → Earth sciences |
| API | Alphabet Phonétique International = AFI | Alfabetul Fonetic Internaţional | In Romanian = LFE | Lizherenneg Fonetikel Etrebroadel | In Breton = МФА | Международната фонетична азбука | In Bulgarian = IPA | Internationales Phonetisches Alphabet | In Tosk = AFI | Alfabet fonètic internacional | In Catalan = IFA | Internacia Fonetika Alfabeto | In Esperanto = IPA | International Phonetic Alphabet | In English = ΔΦΑ | Διεθνές Φωνητικό Αλφάβητο | In Greek = IPA | Internationales Phonetisches Alphabet | In German = AFI | Alfabeto Fonético Internacional | In Spanish = AFI | Alfabeto Fonético Internacional | In Galician = NAF | Nazioarteko Alfabeto Fonetikoa | In Basque = IPA | Internationalt Phonetescht Alphabet | In Letzeburgesh = AFI | Alfabeto Fonetico Internazionale | In Italian = МФА | Международный фонетический алфавит | In Russian = AFI | Alfabeto Fonético Internacional | In Portuguese = AFI | Alfabet fonetic internacionau | In Occitan = AFE | Alfabet Fonetike Eternåcionå | In Walloon = IFA | Internationoal Fonetisch Alfabet | In Vlaams = AFN | Alfabeti Fonetik Ndërkombëtar | In Albanian |
In French | → Writing systems |
| API | American Petroleum Institute | In English | → Standardization → Mining → 665 |
| API | Agence de Promotion de l'Industrie | In French | → Organizations and associations → Industry, industrial policy |
| API | Association des Producteurs Indépendants | In French | → Associations → Cinema, movies |
|