• Adcox 1-A, a biplane built in Portland, USA in 1929
• Alpha 1A, an alpha-amylase human gene
• Alpha-1A adrenergic receptor, a human gene
• Amadeus IT Group, a travel reservation technology company
• Arginine vasopressin receptor 1A, a human gene
• Astra 1A, the first satellite launched and operated by Société Européenne des Satellites
• California Proposition 1A (2004),
• Class 1-A, a classification of the Selective Service System : available for unrestricted military service
• Croatian 1A Volleyball League
• Essex bus routes 1 and 1A
• Interferon beta-1a, a drug in the interferon family
• Little Joe 1A, a 1959 unmanned NASA launch
• Melatonin receptor 1A, a human gene
• Meltwater pulse 1A, a period of rapid deglacialization that took place 14.7-14.2 thousand years ago
• Mercury-Redstone 1A, a 1969 NASA mission
• Metallothionein 1A, a human gene
• MH-1A, a nuclear power reactor and the first floating nuclear power station
• Packard 1A-1500, a 1929 12-cylinder liquid-cooled 60-degree Vee piston aircraft engine
• Pre-1A, a grade in the Jewish day school structure of education
• Secretoglobin, family 1A, member 1 (uteroglobin), a human gene
• ShinMaywa US-1A, a Japanese anti-submarine warfare aircraft
• Sisu 1A, a homebuilt sailplane
• Turksat 1A, a satellite
• 1A (comics) or Magnus, Robot Fighter
• "1-A", a story by Thomas M. Disch

• Amadeus (CRS) nach IATA-Airline-Code
• Astra 1A, ein Fernsehsatellit der SES Global
• Chevrolet 1A, ein Pkw-Modell
• IA Fernsehen, ein privater Berliner TV-Sender
• Schmelzwasserpuls 1A, eine Zeit rapider Entgletscherung zum Ende der letzten Eiszeit

Em 2008 a linha vai ser dividida em duas: a Linha 5 (Erasme/Erasmus - Herrmann-Debroux) e a Linha 6 (Roi Baudouin/Koning Boudewijn - Simonis).