Ordinance - ordnance
These two words look very similar, and the spell-checker will allow you to confuse them. So it is up to you to make sure you know the right one.
- Ordinance means a kind of order or regulation.
- Ordnance is an old word for what is now called 'artillery' – i.e. the 'great guns' of an army. British civilians probably know it best in Ordnance Survey - the name for the series of official maps of the United Kingdom which were originally drawn up by the artillery to assist with the defence of the country. Ordnance Survey maps, in a variety of scales, are generally regarded as the best maps avilable here.