श्री भगवानुवाचइदं शरीरं कौन्तेय क्षेत्रमित्यभिधीयते।एतद्यो वेत्ति तं प्राहुः क्षेत्रज्ञ इति तद्विदः
śhrī-bhagavān uvācha idaṁ śharīraṁ kaunteya kṣhetram ity abhidhīyate etad yo vetti taṁ prāhuḥ kṣhetra-jña iti tad-vidaḥ
Lord Shri Krishna replied: O Arjuna! The body of a person is the playground of the Self; and That which knows the activities of Matter, sages call the Self.
Translated by Shri Purohit Swami
The Blessed Lord said, "O Arjuna, this body is called the field; he who knows it is called the knower of the field by those who know them."
Translated by Swami Sivananda
Word meanings (from the gita/gita dataset)
śhrī-bhagavān uvācha—the Supreme Divine Lord said; idam—this; śharīram—body; kaunteya—Arjun, the son of Kunti; kṣhetram—the field of activities; iti—thus; abhidhīyate—is termed as; etat—this; yaḥ—one who; vetti—knows; tam—that person; prāhuḥ—is called; kṣhetra-jñaḥ—the knower of the field; iti—thus; tat-vidaḥ—those who discern the truth