'Tomorrow' is Old English for 'to the morning' — a fused phrase equating next morning with next day.
The day after today; the near future.
From Old English 'tō morgenne,' meaning 'on the morrow, on the (next) morning.' This is a prepositional phrase that became fused into a single word: 'tō' ('to, on, at') plus 'morgen' ('morning, next day') in the dative case. The Old English 'morgen' meant both 'morning' and 'the following day,' from Proto-Germanic