Hyphen Sleep Coupon, Deals, 40+ Offers, Coupons, Promo Codes 2019. Hyphen Sleep started with a desire to inspire amazing days through amazing nights. We set out to reinvent how the world thinks about sleep. Sure, if you ask Merriam Webster, a hyphen is a “punctuation mark that is used to connect words or parts of words” - but we know that it’s so much more than that. Hyphen is about the connection sleep has to everything else in your life.