Stylo vs. crayon
While stylo and crayon both refer to common writing instruments, they are not interchangeable. The fundamental difference lies in the substance they use to make a mark: a stylo uses ink, whereas a crayon uses a solid pigment core like graphite or wax.
Stylo
A1A stylo is a pen. It is a writing implement that uses liquid ink, which is dispensed through a point. This includes ballpoint pens (stylo-bille), fountain pens (stylo-plume), and felt-tip pens (stylo-feutre).
Peux-tu me prêter un stylo pour remplir ce formulaire ?
(Can you lend me a pen to fill out this form?)
J'ai signé le document avec un stylo noir.
(I signed the document with a black pen.)
Mon stylo-plume a fui dans ma poche.
(My fountain pen leaked in my pocket.)
Ce stylo-bille est très agréable pour écrire.
(This ballpoint pen is very pleasant to write with.)
Oups, je n'ai plus d'encre dans mon stylo.
(Oops, I'm out of ink in my pen.)
Crayon
A1A crayon is a pencil or a crayon. It is a writing or drawing implement with a solid pigment core, such as graphite (a crayon à papier) or colored wax (a crayon de couleur). Its marks can typically be erased.
L'architecte fait ses esquisses avec un crayon à papier.
(The architect makes his sketches with a graphite pencil.)
N'oublie pas de tailler ton crayon avant le test.
(Don't forget to sharpen your pencil before the test.)
Ma fille adore dessiner avec ses crayons de couleur.
(My daughter loves to draw with her colored pencils.)
J'ai fait une erreur, passe-moi la gomme pour effacer ce trait de crayon.
(I made a mistake, pass me the eraser to erase this pencil line.)
Elle utilise un crayon pour les yeux pour se maquiller.
(She uses an eyeliner pencil for her makeup.)
Summary
In short, a stylo is a pen that writes with ink and is generally permanent. A crayon is a pencil that writes with a solid core (like graphite or wax) and is typically erasable. Think stylo for signing documents and crayon for sketching or for tasks where you might need to erase.