schneiden
to cut
To divide or work on something with a sharp object such as a knife or scissors.
Er schneidet das Gemüse für den Salat.
He is cutting the vegetables for the salad.

to cut
Loading your saved state.
to cut
To divide or work on something with a sharp object such as a knife or scissors.
Er schneidet das Gemüse für den Salat.
He is cutting the vegetables for the salad.

Using 'schneiden' with or without a reflexive pronoun changes the meaning. 'Etwas schneiden' means to cut an object into pieces. 'Sich schneiden' means to accidentally injure oneself.
Bitte schneide die Zwiebel in kleine Würfel.
Please cut the onion into small cubes.
To describe how something is cut, you often use a prepositional construction. Typical patterns are 'in Scheiben schneiden' (to cut into slices), 'in Würfel schneiden' (to cut into cubes), or 'in Stücke schneiden' (to cut into pieces).
Für das Gratin müssen wir die Kartoffeln in dünne Scheiben schneiden.
For the gratin, we have to cut the potatoes into thin slices.
When you cut yourself on a specific body part, that body part is often given with 'in' + accusative. The reflexive pronoun then appears in the dative.
Ich habe mich geschnitten.
I cut myself.
When you cut someone's hair, the person whose hair is being cut is in the dative. The direct object is 'die Haare' (the hair).
Kannst du mir bitte die Haare schneiden?
Can you cut my hair, please?
In combination with words like 'Film' (film), 'Video' (video), or 'Ton' (audio/sound), 'schneiden' always means 'to edit' or 'to cut' media.
Die Regisseurin schneidet ihren neuen Film gerade selbst.
The director is currently editing her new film herself.
In the meaning 'to ignore someone', the verb is transitive and needs a person as a direct accusative object. It describes an active, deliberate action.
Nach unserem Streit schneidet er mich komplett.
After our argument, he is completely snubbing me.
The reflexive form 'sich schneiden' is used in mathematics and geometry to describe the point of intersection of lines or surfaces.
Zwei parallele Linien schneiden sich nie.
Two parallel lines never intersect.
The verb 'schneiden' is part of the fixed expression 'eine Grimasse schneiden' (to make a face). Here it has nothing to do with cutting something into pieces, but means 'machen' (to make) or 'ziehen' (to pull).
Der Clown schnitt eine lustige Grimasse, um die Kinder zum Lachen zu bringen.
The clown made a funny face to make the children laugh.
to process / edit
'schneiden' and 'bearbeiten' can both mean that you change something. 'schneiden' is more specific when you separate something into parts with a knife, scissors, or in a film or audio program. 'bearbeiten' is broader: you can make a photo brighter, improve a text, or shape wood with tools. The words can be confused because 'Schneiden' is sometimes part of editing or working on something, especially with videos or materials. If the separating is important, 'schneiden' fits; if it is generally about changing or improving something, 'bearbeiten' is better.

Für den Salat schneidet Tom die Gurke in dünne Scheiben.
For the salad, Tom cuts the cucumber into thin slices.
Lena bearbeitet das Foto, weil es zu dunkel ist.
Lena edits the photo because it is too dark.