<p><strong>Preposition</strong></p><ul><li>up and on; upward so as to get or be on: He climbed upon his horse and rode off.</li><li>in an elevated position on: There is a television antenna upon every house in the neighborhood.</li><li>in or into complete or approximate contact with, as an attacker or an important or pressing occasion: The enemy was upon us and our soldiers had little time to escape.</li><li>immediately or very soon after: She went into mourning upon her husband's death.</li><li>on the occasion of: She was joyful upon seeing her child take his first steps.</li><li>on (in any of various senses, used as an equivalent of on with no added idea of ascent or elevation, and preferred in certain cases only for euphonic or metrical reasons): He swore upon his honor as a gentleman.</li></ul>