Ma'anar ƙamus na "ƙarfin filin" shine ƙarfi ko girman filin zahiri, kamar filin lantarki, filin gravitational, ko filin lantarki. Ma'auni ne na yawan ƙarfin da filin ke yi kan wani abu a cikin iyakar tasirinsa. Ana auna ƙarfin filin sau da yawa a cikin raka'a kamar volts a kowace mita (V/m) ko teslas (T), dangane da nau'in filin da ake aunawa. A cikin ilimin kimiyyar lissafi, ƙarfin filin muhimmin ra'ayi ne da ake amfani da shi a fagage daban-daban, gami da electromagnetism, injiniyoyi na ƙididdigewa, da alaƙa gabaɗaya.