• The definite article meaning “the” is el  for masculine singular nouns. Notice that el without the accent mark is the article… what does él mean? That’s right it means “he”. Don’t confuse el and él!
  • Most words ending in –o are masculine

el chico
el libro
el cuaderno 

• • Many words ending in –ma are masculine (and originated from the Greek language):

el problema
el clima
el idioma 

• Many nouns end in –e.  While statistically more are masculine than feminine, there is no firm rule for these and you need to memorize their gender when learning their meaning:

la clase
el diente (tooth)
el coche (car)

• Many nouns that end in consonants other than -d or -z are masculine, but again this is not a firm rule and you must memorize their gender:

el honor (honor)
el hospital (hospital)
el hotel (hotel)

• There are other nouns that do not clearly reveal their gender, so it is important that you memorize them.

el pupitre
el lápiz
el reloj
la luz
la pared

• There are some exceptions that you have to remember:

el día
el mapa
la mano
la foto
la moto (motorcycle)

2. People:

• When referring to people, the biological sex of a person will determine a word’s gender regardless of the rules described above. However, as society has become more sensitive to sexism, as well as questions of gender and sexual identity, people have begun experimenting with ways to adjust the traditional binary-gendered structure of the Spanish language. Click the link below to explore some of the experiments in gender-neutral language that Spanish speakers have been developing.
  https://nonbinary.wiki/wiki/Gender_neutral_language_in_Spanish
• Some nouns for people will be identical except for the -o or -a ending:

el muchacho (boy)
la muchacha (girl)
el niño (male child)
la niña (female child)
el maestro (male teacher)
la maestra (female teacher)
el compañero de clase (male classmate)
la compañera de clase (female classmate)
el amigo (male friend)
la amiga (female friend)

• However, other nouns are completely different for masculine and feminine forms:

el hombre (man)
la mujer (woman)

• Some nouns for people are identical, and the gender is shown only in the definite article:

el estudiante (male student)
la estudiante (female student)
el dentista (male dentist)
la dentista (female dentist)

Remember! The gender of nouns that do not refer to people is an inherent characteristic that cannot be changed.  If you change the gender ending of an inanimate object, you can be changing the meaning of the noun to another legitimate word in Spanish:

• el caso (case)
  la casa (house)
• el puerto (port)
  la puerta (door)
• el Papa (the Pope)
  la papa (potato)
• el libro (book)
  la libra (pound)