tufa /tooˈfə, tūˈfə/

1. Calc-sinter (often calcareous tufa)
2. Tuff or other porous rock (obsolete)

• song sparrows
• songster
• songsters
• songstress
• songstresses
• song thrush
• stand-ins
• stand in the gate
• stand in with
• standish
• standishes
• stand low
• stand off
• stand-off
• standoff
• stand off and on
• stand-off half
• stand-off halves
• standoffish
• standoffishness
• standoffishnesses
• stand-offs
• stand oil
• stand on
• stand on ceremony