Definition of first :
1. Before any other person or thing in time, space, rank, etc.; - much used in composition with adjectives and participles.
2. Foremost; in front of, or in advance of, all others.
3. Most eminent or exalted; most excellent; chief; highest; as, Demosthenes was the first orator of Greece.
4. Preceding all others of a series or kind; the ordinal of one; earliest; as, the first day of a month; the first year of a reign.
5. The upper part of a duet, trio, etc., either vocal or instrumental; - so called because it generally expresses the air, and has a preeminence in the combined effect.
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beginning (part of speech: adjective)
formative, infant, inaugural, maiden, fetal, commencing, initial, early, dawned, preparatory, Genesis, foremost, beginning, nascent, primal, primeval, germinal, introductory, aboriginal, hatching, alpha, newborn, new, original, precursory, incipient, preliminary, embryonic, sprouting, primordial, budding, emerging, infantile, starting, baby
original (part of speech: adjective)
firstly (part of speech: adverb)