<p><strong>Noun:</strong></p><ul><li>The fourth letter of the Greek alphabet (Δ, δ).</li><li>The consonant sound represented by this letter.</li><li>The fourth in a series of items.</li><li>Anything triangular, like the Greek capital delta (Δ).</li><li>Mathematics: an incremental change in a variable, as Δ or δ.</li><li>A nearly flat plain of alluvial deposit between diverging branches of the mouth of a river, often, though not necessarily, triangular: the Nile delta.</li><li>Also Delta.</li><li>A word used in communications to represent the letter D.</li><li>Delta, Astronomy: a star that is usually the fourth brightest of a constellation: The fourth brightest star in the Southern Cross is Delta Crucis.</li></ul><p><strong>End of Response</strong></p>