Classical Arabic - English Dictionary

مَعَ [generally thus in all cases] is a word, or noun, (Ṣ, Ḳ,) or particle, (Ḳ,) denoting concomitance, (Ṣ, Ḳ,), &c. (Ḳ.) It is said to denote the commencement of concomitance, though this is not invariably the case. (MF and TA, voce فِى.)

جِئْتُ مَعَ العَصْرِ means عِنْدَ العَصْرِ. (Mughnee.)