ḥarf / حرف

The third category of Arabic words. Literally means “letter” because lots of the ḥurūf حروف  are letters, but this category includes all prepositions, connectors and articles. A way to determine whether a part of speech is whether it carries meaning all by itself. For example “على ” = “on” doesn’t carry meaning without another word like “الأرض ” = “the ground”.