abacus /abˈə-kəs/

1. A counting frame, consisting of horizontal rods along which movable beads can be slid
2. A level tablet on the capital of a column, supporting the entablature (architecture)

• harder
• hardest
• hardface
• hard-faced
• hardfaces
• hard facts
• hard-favoured
• hard-favouredness
• hard-featured
• hard-featuredness
• hard feelings
• hard-fern
• hard-ferns
• hard-fisted
• hard-fought
• hard going
• hard-got
• hard-gotten
• hard-grained
• hardgrass
• hardgrasses
• hardhack
• hardhacks
• hard-handed
• hard hat