Concise Bible Dictionary:

The inherent qualities of a being manifested in the various characteristics which mark and display its existence: the aggregate of such qualities is what is termed its nature, and one class or order of being is thus distinguished from another. Men by nature are the children of wrath (Eph. 2:3); whereas the Christian becomes morally partaker of the divine nature (2 Peter 1:4); of which love is the characteristic: he is made partaker of God’s holiness (Heb. 12:10). The work of God in the Christian which forms his nature thus finds its expression in him. The Creator can design and predicate the nature of a being before that being has an actual existence in fact; but we, as creatures, can discern the nature only from the existent being, and cannot therefore rightly speak of the nature save as characteristic of the being.
Nature is also a term descriptive of the vast system of created things around us, to each part of which the Creator has given not only its existence, but its use, its order, its increase, its decay—often called the “laws of nature”—the laws which govern each and which constitute its propriety. Thus nature teaches that a man should not have long hair (1 Cor. 11:14); and a multitude of other things that are of God’s order in creation.