Modern Standard Arabic grammar defines a detailed part-of-speech hierarchy which is applied to words and morphological segments both. Fundamentally, a word may be classified as a nominal ism (اسم), verb fiʿil (فعل) or a particle ḥarf (حرف). The set of nominals include nouns, pronouns, adjectives and adverbs. The particles include prepositions, conjunctions and interrogatives, as well as many others. Morphological annotation in the Arabic corpus divides words into multiple segments. Each segment is assigned a part-of-speech tag. These tags are detailed in the following sections. In addition to part-of-speech tags, each segment is annotated using a set of multiple morphological features.