sparteine /spärˈtē-ēn or -in/

An oily three-ringed alkaloid (C₁₅H₂₆N₂), obtained from the branches of the common broom plant and the seeds of the lupin, sometimes used to treat heart irregularities

• on terms
• on that score
• on the agenda
• on the air
• on the alert
• on the anvil
• on the back burner
• on the back foot
• on the back of
• on the back of an envelope
• on the ball
• on the barrelhead
• on the bash
• on the batter
• on the beam
• on the bench
• on the bias
• on the bit
• on the blink
• on the block
• on the boil
• on the bone
• on the bot
• on the bounce
• on the bow hand