From Longman Dictionary of Contemporary Englishwi-fiwi-fi /ˈwaɪ faɪ/ ●●○ (also wireless networking) noun [uncountable] trademark (wireless fidelity) a way of connecting computers or other electronic machines to a network by using radio signals rather than wiresFrom Longman Business DictionaryWi-FiWi-Fi /ˈwaɪfaɪ/ (also WiFi), wi-fi noun [uncountable] COMPUTINGTELECOMMUNICATIONS (wireless fidelity) a way of connecting computers or other electronic machines to a network or the Internet by using radio signals rather than wires