Traveling toward or heading in the direction of the east.
English compound: 'east' (Old English 'east,' from Proto-Germanic 'austro-') + 'bound' (Old English 'bunden,' past participle of 'bindan,' meaning 'tied' or 'destined for').
Before GPS, people navigated by the sun's position—'eastbound' had real meaning because everyone knew the sun rises in the east, making it an instantly recognizable direction marker.
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