But it's not that simple...

I know you mean bottom sounding, but some readers may be confused

BS Bachelor of Science
BS Backspace
BS Bull Stuff (polite form)
BS British Standards
BS Basel-Stadt (canton postcode, Switzerland)
BS Baby Shower
BS Bristol (postcode, United Kingdom)
BS Britney Spears
BS Box Score
BS Baltimore Sun (newspaper)
BS Brescia (Lombardia, Italy)
BS Bookstore
BS Back to School
BS Base Station
BS Braunschweig, Germany
BS Bahamas (country code and domain code)
BS Business Services
BS Balance Sheet
BS Blood Sugar
BS Blue Sky
BS Business System
BS Baking Soda
BS Business Studies
BS Bisexual
BS Big Screen
BS Boy Scouts
BS Bible Study
BS Be Smart
BS Bariatric Surgery (weight loss)
BS Backside (extreme sports)
BS Blue Springs (Missouri)
BS Boot Sector
BS Basel Stadt (Basel Town; Suisse Half Canton)
BS Bruce Springsteen
BS Berufsschule (German: vocational school)
BS Big Sister
BS Brushed Stainless (product feature)
BS Broadcasting System
BS Barbra Streisand
BS Be Sweet
BS Bioshock (game)
BS Buffalo Sabres (NHL)
BS Black Sabbath (band)
BS Briggs & Stratton (Wauwatosa, WI)
BS Be Specific
BS Blacksmith (gaming, Ultima Online)
BS Big Show (WWE wrestler)
BS Big Shot
BS Back Stage
BS Big Smile (Internet chat)
BS Bad Science
BS Bronze Star
BS Back Side (skate term)
BS Brown Sugar
BS Bath Salt
BS Battlestations
BS Bering Sea
BS Barber Shop
BS Boondock Saints (movie)
BS Blind Spot
BS Beauty Shop
BS Brain Stem
BS BOINC (Berkeley Open Infrastructure for Network Computing)
BS Boob Squish (mammogram)
BS Balanced Scorecard
BS Business Segment
BS B-Spline
BS Bart Simpson
BS Billing System
BS Backstab (Starcraft game)
BS Backing Store
BS Bob Seger
BS Black Scholes (option pricing model)
BS Brothers & Sisters
BS Band Saw
BS Broken Saints (webcomic)
BS Bomb Squad
BS Blood Star (Diablo game)
BS Bus Schedule
BS Blood Stained (Everquest)
BS Bachelor of Surgery
BS Boz Scaggs
BS Bishop's Stortford (England, UK)
BS Big Smoke (gaming character, GTA:SA)
BS Blessed Sacrament
BS Bill of Sale
BS Beam Splitter
BS Basic Strategy (blackjack card game)
BS Boot Sequence
BS Boolean Search
BS Bull Snot (polite form)
BS Black Stallion
BS Backstroke (swimming)
BS Blown Save (baseball)
BS Broadcast Satellite
BS Breaking Strength
BS Bombardment Squadron
BS Bering Strait
BS Motor Starter (motor-driven cam type)
BS Breath Sounds
BS Belt Sander
BS Basic Software
BS Broadcasting Satellite
BS Biochemical Society (London, UK)
BS Beta Sigma (fraternity)
BS Bound States
BS Bright and Shiny (recycling)
BS Blowing Snow (weather reports)
BS BetalingsService (Danish: Payment Service)
BS Blocked Shot (basketball)
BS Broken Stowage (shipping)
BS Butthole Surfers (band)
BS Best Speaker (Toastmasters)
BS Bow String (Runescape gaming)
BS Boundary Scan
BS Block Sorting
BS Bungie Studios (gaming company)
BS Broadcast Source (US DoD)
BS Belgisch Staatsblad (Dutch; Belgian government publication)
BS Bonus Stage (cartoon)
BS Bloom Syndrome
BS Bowel Sounds (medical)
BS Buy Stop (trading markets; stocks, bonds, commodities)
BS Breast Stroke
BS Blazin' Squad (band)
BS Burst Size
BS Bend Stiffener (petroleum industry)
BS Bass Saxophone
BS Blue Seed (anime)
BS Back Stock
BS Bungie Software (Microsoft-owned game developer)
BS Boundary Stone (UK maps)
BS Budgetary Support
BS BellSouth Corp. (telephone company)
BS Basic Sediment
BS Busch Sulzer (ship engine)
BS Binnenlandse Strijdkrachten (Dutch)
BS Battle Staff
BS Boiler, Steam
BS Brittany Spaniel
BS Ballistic Skill (gaming)
BS Bovine Scatology
BS Breaking Strain
BS Black Shot (game)
BS Body Shopping (bringing in foreign contractors to work for the US companies at lower salaries)
BS Billy Squire (rock singer)
BS Bore Sight
BS Bolivar(s) (Venezuelan currency)
BS BotServ (IRC Bot Server)
BS Bonus Stage (band)
BS Bank of Slovenia
BS Back Sight (surveying)
BS Bluespec (filename extension)
BS Bulk Store
BS Bellow Sealed (plumbing)
BS Broadcast Satellaview (Super Nintendo Entertainment System)
BS Betrayed Spouse
BS Bailter Space (band)
BS Birth Son (adoption)
BS Balance Shafts (Nissan)
BS Bentonite slurry (tunnel boring machines)
BS Bank of Springfield (The Simpsons)
BS Block Specification
BS Bird Screen (drawings for HVAC fan or louver accessory)
BS Bitch Shield
BS Biden Shot (political slang)
BS Bipolar Signal
BS Brodosplit (Shipyard Company, Split, Croatia)
BS Basin Slope
BS Bohemia Suburbana (Guatemala rock group)
BS Blocking Series
BS Bungie Sightings (bs.bungie.org)
BS Bit Synchronizer
BS Bio-Son
BS Bina Swadaya
BS Battle Sphere (Atari Jaguar video game)
BS Berkhouse/Snyder (music duo)
BS Boston Stoker (coffee company)
BS Bi-Synchronous
BS Battle Support
BS Business Stupidity (opposite of Business Intelligence)
BS Bjarne Stroustroup (creator of C++ language)
BS Blister Steel
BS Blazing Swamp (Lineage 2 game)
BS Bis Spater (German: see you later)
BS Bitumen Solution
BS Bien-Etre Sociale (Canadian French: welfare)
BS Barfko Swill (Frank Zappa Production Company)
BS Bi-Metallic Strip
BS Bon Scot (singer)
BS Bayesian Score
BS Birchwood School (West Nyack, NY)
BS Blank Sentences
BS Bottom Sounding
BS BASIC or cyBASIC (file extension)
BS Before Stinson (How I Met Your Mother; TV series reference)
BS Black Sheep Brotherhood (gaming community)
BS Broadband Storm
BS Béton de Sable (French: Sand Concrete)
BS Behavioral Statement
BS Bike Stunt Competition
BS BioShelf International (Hamilton, ON, Canada)
BS Brainstorm/Brainstorms/Brainstorming/Brainstormed
BS Britstorm