I think short-term debt or standard deviation.
Apparently there are more…
Acronym Definition
STD Standard
STD Sexually Transmitted Disease
STD Stunde (German: Hour)
STD Doctor(ate) of Sacred Theology (degree)
STD Short Term Disability
STD Short Term Disability (Insurance)
STD Standing
STD Stunden (German: Hours)
STD Steady
STD Standard Deviation
STD Sustainable Tourism Development (various locations)
STD Standard Transmission (car transmission)
STD Save the Date
STD Steward
STD Spot the Differences (games)
STD State Transportation Department
STD Solar Terrestrial Dispatch
STD Security Tools Distribution (Knoppix)
STD Storage Tank Division (various locations)
STD Saves the Day (band)
STD Savings Tax Directive (EU)
STD São Tome and Principe Dobra (ISO currency code)
STD St. David
STD Svensk Teknik och Design (Swedish: Swedish Engineering and Design)
STD Spyro the Dragon (game)
STD Set Direction
STD Selection Transmit Diversity
STD Semantic Type Definition
STD Super Twist Display
STD Sunbeam Talbot Darracq
STD Suspend to Disk
STD Save to Disk
STD Sacred Theology Degree (various schools)
STD State Transition Diagram
STD Short Term Debt (finance)
STD Seize the Day
STD Stabbed to Death (band)
STD Straight to DVD (Digital Versatile Disc)
STD Software Test Description
STD Star Destroyer (Star Wars)
STD Subscriber Trunk Dialing
STD Servicing Transfer Disclosure (finance)
STD Studiendirektor
STD Sigma Tau Delta (Sorority and English Honors Society)
STD Stud Book
STD Shaggy 2 Dope (Insane Clown Posse band member)
STD Severe Tire Damage (band)
STD Science and Technology Division
STD Scheduled Time of Departure
STD Second To Die (life insurance)
STD Set Direction Flag
STD Slant Tropospheric Delay (weather modeling)
STD Saturation Transfer Difference
STD Science and Technology for Development (European Union)
STD Salinity, Temperature, Depth
STD Synthetic Training Device
STD Software Test Design
STD Schaffer the Darklord (entertainer)
STD Special Taxing District
STD Sexual Tension Detroit (Detroit, MI)
STD Santo Domingo, Venezuela - Mayor Humberto Vivas Guerrero (Airport Code)
STD Standard Trunk Dialing
STD South Tibetan Detachment
STD Société des Touristes du Dauphiné (French: Tourists Society of Dauphin; France)
STD Small Target Detection
STD Sustainable Technology Development (Netherlands)
STD Socially-Transmitted Disease (aka Sexually-Transmitted Disease)
STD Software Test Document
STD Safely Tolerated Dose
STD Serial Transmit Data
STD Spécifications Techniques Détaillées (French: Detailed Technical Specifications)
STD Selective Transmit Diversity
STD Stick the Dealer (euchre)
STD Screw the Dealer (Euchre card game house rule)
STD Storage Technology Division
STD Space-Time Diagram
STD Sub Tropical Depression
STD Simplified Trellis Decoder
STD Step Transaction Doctrine
STD Student Technical Director
STD Shuttle Test Director (US NASA)
STD Sham Tseng Development (Hong Kong)
STD Skate Till Death (skateboarding group)
STD System Technology Demonstrator
STD Spanish Training Division
STD Stephen, Thomas, Dalton (Sacramento band)
STD Station de Traitement des Déchets (French: Waste Treatment Station)
STD Singly-Testable Dependent
STD Spatial-Temporal Detector
STD Spectral Theory of Diffraction
STD Solutions for the Disturbed (band)
STD Systems Target Decoder (MPEG systems)
STD Society for Theological Discussion
STD Subcutaneous Tissue Disorder
STD Steps to Dance (dance school; California)
STD Single-Trial Decoding
STD Standard Offline Test Driver
STD System Test Directive
STD Swimmer Transportation Device
STD Physically on Board under Instruction; Not Ship’s Company (US Navy)