From Wiktionary, the free dictionary
From ב־ (b'-, “in, with”) + עיקר (ikár, “main thing”).
בעיקר / בְּעִקָּר • (b'ikár)
- Principally, mainly, primarily, especially, particularly.
- עיקרי (ikarí, “principal, primary, main”)
Borrowed from Hebrew בְּעִקָּר.
בעיקר
- principally