मातरिश्वा is derived from मातरिश्वन्
मातरिश्वा means मातरि अन्तरीक्षे श्वयति इति ( air which blew in space )
मातरिश्वा is another name for Vayu Devata
Following is mentions for this word –
तदभ्यद्रवत्तमभ्यवदत् कोऽसीति वायुर्वा अहमस्मीत्यब्रवीन्मातरिश्वा वा अहमस्मीति ( Keno Upanishad 3.8 )
As mentioned by Adi Shankaracharya in his commentary for the above verse
मातर्यन्तरिक्षे श्वयतीति मातरिश्वा – Since this air goes to the outer space so it called as “Matarishva”
इदं सर्वमपि आददीय गृह्णीयां यदिदं पृथिव्याम – Whatever there is on this earth, air can hold all so it called as “Matarishva”
