1. For fear that, in order to prevent
   "she tiptoed lest her mother should hear her" 
2. In case
   "he worried lest he should be late"

Encyclopedia: Lest

• Spanish bayonet
• Spanish broom
• Spanish burgoo
• Spanish capital
• Spanish cedar
• Spanish cedar tree
• Spanish chestnut
• Spanish Civil War
• Spanish dagger
• Spanish elm
• Spanish fly
• Spanish garlic
• Spanish gorse
• Spanish grunt
• Spanish Guinea
• Spanish heath
• Spanish Inquisition
• Spanish iris
• Spanish lime
• Spanish lime tree
• Spanish mackerel
• Spanish monetary unit
• Spanish moss
• Spanish needles
• Spanish oak