Air is a mixture of gases, and the crossword solutions for the term 'air, constituent of' are XENON (5 letters), ARGON (5 letters), NEON (4 letters), HELIUM (6 letters), OXYGEN (6 letters), and NITROGEN (8 letters). XENON is a noble gas that is colorless, odorless, and tasteless. ARGON is also a noble gas that is colorless, odorless, and tasteless. NEON is another noble gas that is also colorless, odorless, and tasteless, but it glows reddish-orange when exposed to an electric current. HELIUM is a noble gas that is lighter than air and is used in balloons and blimps. OXYGEN is a colorless, odorless, and tasteless gas that is essential for human life. NITROGEN is a colorless, odorless, and tasteless gas that makes up 78% of the Earth's atmosphere.