What is BSL? BSL stands for Bra Strap Length. This makes reference to hair which extends down to the level of the bra strap. POSTS RELATED TO THIS TERM Terminal Length – How Long Can Your Hair Actually Grow? 7 Ways To Embrace The Length Of Your Natural Hair At Any Stage … How To Get 4b Hair To Waist Length In 3 Years Related Posts:What is CBL?What is MBL?What Is APL?What is the LOC or LCO method?What Does DC Or DT Mean?What is SLS?What is HG?What Does HH Mean? TweetPinShare0 Shares Black Hair Information > Glossary > What is BSL?