Water has a density of 1000 kg/m3 by standard definition at its temperature of maximum density 3.98 Â°C and at 0% salinity. Scientists and engineers use water as a baseline for comparing the relative density of various materials. Water with a density of 1000 kg/m3 at 3.98 Â°C has a mass of 1000kg and a volume of 1 m3.
Spelt is a word. It is the past participle of spell. It is also a type of wheat, and therefore also a noun. It depends upon whether you are using British English (and Spelt is correct) or you are using American English.
If they are pronounced differently then they are also heteronyms â for example, bow (the front of a ship) and bow (a ranged weapon). Homophones (literally same sound) are usually defined as words that share the same pronunciation, regardless of how they are spelled. If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally different writing).