श्री भगवानुवाचइदं शरीरं कौन्तेय क्षेत्रमित्यभिधीयते। एतद्यो वेत्ति तं प्राहुः क्षेत्रज्ञ इति तद्विदः ॥

idaṁ śharīraṁ kaunteya kṣhetram ity abhidhīyate etad yo vetti taṁ prāhuḥ kṣhetra-jña iti tad-vidaḥ

This body, son of Kuntî, is called the Field; that which knoweth it is called the Knower of the Field by the Sages.

In plain words: Krishna explains that the body is called the "Field," and the one inside who is aware of it is called the "Knower of the Field."