Tim Bowen tackles word grammar on the ground.

Apart from its use as a noun, ground can also function as a verb and an adjective. 

As a noun, it is mainly used in the singular (on the ground, below ground etc), but can also be used in the plural to refer to the land and gardens that surround a large house, as in ‘She found him wandering around the grounds’ or ‘The castle boasts extensive grounds’. 

Also used in the plural, grounds can also mean the reason for what someone says or does, or for being allowed to say or do something, as in ‘There seem to be no grounds for this complaint’ or ‘The Army turned him down on medical grounds’. Grounds can also mean the residue of crushed coffee beans after coffee has been made, as in ‘She claims to be able to read people’s future from their coffee grounds’. 

The verb to ground can mean to prevent a plane from leaving the ground, as in ‘All flights have been grounded as a result of the foggy conditions’. It can also mean to punish a child or young person by stopping them from going to places they enjoy, as in ‘His parents grounded him for two weeks for smoking’. Usually used in the passive voice, ground can also mean to base a decision or idea on a particular thing, as in ‘Any new policies needed to be firmly grounded in a careful analysis of the issues’. 

As an adjective ground can be used to mean crushed (the past participle of grind), as in ‘For best results, use freshly ground black pepper’, or it can refer to the noun ground, in which case it is only used in a pre-nominal position, as in ‘Air attacks have produced results but some politicians are calling for a ground assault’.