Undoubtedly the zina for which a person is to be punished in the manner described above is penetration, where the private parts meet. As for the things that lead to zina, such as touching, kissing ..... although they are haraam and abhorrent, the one who does them may be punished for doing them, but he is not punished with the hadd punishment that is meted out to the zaani; rather he should be rebuked and disciplined. As for naming, sharee’ah calls these actions zina, as it says in the hadeeth narrated by al-Bukhaari (6243) and Muslim (2657) from Abu Hurayrah (may Allaah be pleased with him) from the Prophet (peace and blessings of Allaah be upon him) who said: “Allaah has decreed for the son of Adam his share of zina which will inevitably catch up with him. The zina of the eye is looking and the zina of the tongue is speaking. The heart wishes and longs and the private part confirms that or denies it.”
According to the version narrated by Muslim: “The zina of the eyes is looking, the zina of the ears is listening, the zina of the tongue is speaking, the zina of the hand is touching, and the zina of the foot is walking. The heart wishes and longs and the private part confirms that or denies it.”
Ibn Battaal (may Allaah have mercy on him) said: Looking and speaking are called zina because they invite one to true zina. Hence he said: “the private part confirms that or denies it.” End quote from Fath al-Baari.