SPANISH HELP Please??

A noun is masculine when it ends in -o. It's feminine when it ends in -a, -cion, - sion, -dad, -tad, -tud, -umbre. It can be masculine or feminine if it ends in -nte, -e, or -ista. There are irregulars that just have to be memorized such as: la mano, la radio, la foto, el dia, el drama, el mapa. In the case of este or esta, I believe you're talking about demonstrative pronouns (this, these, those). Este (this) is singular masculine. Estos (these) is plural masculine. Esta is singular feminine. Estas is plural feminine. You also have Ese (that), esos, esa, esas. Or aquel (those over there), aquellos, aquella, aquellas.