The word "adreamed" is spelled the way it is to reflect its pronunciation. The IPA phonetic transcription for this word is /əˈdriːmd/ where the stress falls on the second syllable. This indicates that the word is pronounced with a schwa sound in the first syllable, followed by a long 'e' sound, and ending with a 'd' sound. Adreamed means something that has been dreamed about or imagined. It is derived from the verb "to dream" which means to have a series of thoughts or images while sleeping.
The word "adreamed" is derived from the Middle English word "adremen" which meant "to dream". This Middle English term itself came from the Old English word "adreman" or "adreman" which had a similar meaning.