Tb terbium Ta tantalum sw, swa Swahili SW south-west sv, swe Swedish Sun., Su Sunday SSW south-south-west ssp, LSE Spanish Sign Language SSE south-south-east Sr strontium Sn tin SMTP simple mail transfer protocol SMS short message service Sm samarium sl, slv Slovenian sk, slk Slovak sim subscriber identity module Si silicon SGML standard generalised markup language Sg seaborgium Sept., S September SEN special educational needs Se selenium SE south-east SDG sustainable development goal