The name Krishna has six meanings as given in Garga Bhagavatam (1.15.28–30):
सद्यः प्राणि-पवित्राणि
जगतां मङ्गलानि च
क-कारः कमला-कान्त
ऋ-कारो राम इत्य् अपि 1.15.28
His names at once purify the living entities. His names are the auspiciousness of all the universes. In His name the letter क-कारः stands for Kamalā-kānta (the husband of the goddess of fortune). ऋ-कार: stands for Rāma (the supreme enjoyer).
ष-कारः षड्-गुण-पतिः
श्वेतद्वीप-निवास-कृत्
ण-कारो नारसिंहो ऽयम्
अ-करो ह्य् अक्षरो ऽग्नि-भुक् 1.15.29
ष-कारः - stands for Ṣaḍ-guṇa-pati (the master of six opulences) or Śvetadvīpa-nivāsa-kṛt (The Lord who resides in Śvetadvīpa). ण-कार: stands for Lord Nṛsiṃha. अ-कर: stands for Akṣara (the immortal) or Agni-bhuk (the Lord who enjoys the offerings of agni-hotra yajñas).
विसर्गौ च तथा ह्य् एतौ
नर-नारायणाव् ऋषी
सम्प्रलीनाश् च षट् पूर्णा
यस्मिन् च्छुद्धे महात्मनि 1.15.30
The letter Ḥ(विसर्ग:) stands for Nara-Nārāyaṇa Ṛṣi. In this way these six letters combine to become the name of the pure Supreme Person.