नर हे एका जीवाचे लिंग आहे जे शुक्राणू म्हणून ओळखले जाणारे गेमेट तयार करते, जे गर्भाधान प्रक्रियेत मोठ्या मादी गेमेट, किंवा बीजांडाशी जुळते. द्विलिंगी प्राण्यांमधील पुरुषबीजे तयार करणाऱ्या प्राण्याला नर असे म्हणतात.

Male is the sex of an organism that produces the gamete known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilisation. A male organism cannot reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and asexually. Most male mammals, including male humans, have a Y chromosome, which codes for the production of larger amounts of testosterone to develop male reproductive organs.