seitlich
lateral / sideways
Describes a position or direction that is located at the side of something, comes from the side, or goes to the side.
Das Auto hat einen seitlichen Kratzer an der Tür.
The car has a lateral scratch on the door.

lateral / sideways
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lateral / sideways
Describes a position or direction that is located at the side of something, comes from the side, or goes to the side.
Das Auto hat einen seitlichen Kratzer an der Tür.
The car has a lateral scratch on the door.

The adjective 'seitlich' (lateral/sideways) is derived from the noun 'die Seite' (the side). The ending '-lich' turns it into an adjective meaning 'like a side' or 'belonging to the side'.
Das Haus hat einen praktischen seitlichen Eingang direkt in die Küche.
The house has a practical side entrance directly into the kitchen.
'Seitlich' can stand before a noun as an adjective or describe an action as an adverb. As an adjective, it is declined; as an adverb, it remains unchanged.
Der seitliche Airbag hat bei dem Unfall ausgelöst.
The side airbag deployed in the accident.
'Seitlich' is often used to describe positions or movements in space. Common combinations are 'der seitliche Abstand' (the lateral distance), 'ein seitlicher Blick' (a sideways glance), 'seitlich einparken' (to park sideways), or 'sich seitlich hinlegen' (to lie down on one's side).
Beim Einparken musst du den seitlichen Abstand zum anderen Auto beachten.
When parking, you have to pay attention to the lateral distance from the other car.
next to / besides
'neben' and 'seitlich' can both describe a position at the side. 'neben' is a preposition and directly connects two things: something is next to the bed, or you put something next to the bed. 'seitlich' is an adjective or adverb and describes more the type of position or direction: something is attached at the side, comes from the side, or moves to the side. Learners may confuse the words because both can mean 'at the side'. If you name a specific thing as the reference point, 'neben' is usually more natural. If you are generally describing a side position or sideways direction, 'seitlich' fits better.

Wegen der Sonne setzt sich Frau Hoffmann seitlich ans Fenster.
Because of the sun, Mrs. Hoffmann sits sideways by the window.
Wir haben uns im Kino neben die Tür gesetzt.
We sat down next to the door in the movie theater.