Minecraft wiki entry for Taxicab_distance, associated text: Mob despawning range in Java Edition.
Disks in rivers and lakes generate as blocks within a Euclidean distance from a central block.
Effects of explosions.
Lightning rods redirect lightning within a Euclidean spherical volume centered on the rod, having a radius of 128 blocks in Java Edition and 64 blocks in Bedrock Edition.
The /locate command.
Nether portal searches for destination portals.
Splash potions affect mobs inside a 4-block radius Euclidean sphere.
Target selectors used in commands use Euclidean distances.
A zombie siege is started based on Euclidean distance between a player and the village center.
Finally, a splash text displays the misspelled word "Euclidian!"