Arco or Arca? Unraveling the Differences Between Two Spanish Nouns

This week, we target another pair of Spanish nouns that, while similar in form, carry entirely different meanings based on their gender and ending: arco (masculine) and arca (feminine).

Arco (Masculine)
Pronounced with an -o ending, arco typically refers to curved structures or forms. Here’s how it is used across various contexts:

1. Arc (Geometric Curve)

   • En la superficie de una esfera, la distancia más corta entre dos puntos es el arco de círculo que pasa por ellos.
     (The shortest distance between two points on the surface of a sphere is the arc of the circle that goes through them.)
   • El vehículo describió un arco sobre el Océano Pacífico.
     (The vehicle described an arc over the Pacific Ocean.)

2. Arch (Architectural or Natural)

   • debajo de los arcos del Coliseo (under the arches of the Coliseum)
   • un puente de un solo arco (a single-arch bridge)
   • los arcos plantares (the arches of the feet)

3. Bow (Weapon or Musical Tool)

   • Defenderemos nuestro territorio aunque sea con arcos y flechas.
     (We will defend our land even if it’s with bows and arrows.)
   • Vibran las cuerdas bajo el arco.
     (The strings vibrate beneath the bow.)

4. Rainbow
   Did you know that un arcoíris means "rainbow"?

   • todos los colores del arco iris (all the colors of the rainbow)

5. Football Terminology
   In football, el arco can mean the goal area:

   • las redes del arco (the goal net)

Arca (Feminine)
With an -a ending, arca signifies a chest or coffer in the context of furniture, or it can mean an ark. Despite being feminine, arca is one of a select group of nouns that take the masculine articles el and un in singular form to avoid sound clashes:

1. Chest or Coffer

   • Nunca se atrevió a destapar el arca. (He never dared open the chest.)
   • Levantó la tapa de un arca. (She lifted the lid of a chest.)
   • Adjectives used with arca retain feminine endings:
     • Guardaba sus cartas en un arca perfumada. (She kept his letters in a scented chest.)
     • el arca Labrada (the carved chest)

   In the plural, arcas follows normal feminine plural articles:

   • las arcas familiares (the family coffers)
   • la realidad de unas arcas públicas cada vez más vacías (the reality of increasingly empty public coffers)

2. Ark
   Arca also refers to Noah’s ark or similar biblical contexts:

   • el arca de Noé (Noah’s ark)
   • el arca bíblica (the biblical ark)
   • La paloma regresó al arca con una rama de olivo. (The dove returned to the ark with an olive branch.)

Come back next week as we continue to explore pairs of Spanish nouns whose meanings change with their gender and endings!