Why do japanese ships have MARU in their name?

Question

e.g. bushido maru, nippon maru, tokyo maru

Answer 1

Loosely translates as "the ship named", e.g "the ship named Bushido" etc.

Answer 2

The word maru (丸, meaning "circle") is often attached to Japanese ship names. There are several theories associated with this practice.

(The most common): That ships were thought of as floating castles, and the word referred to the defensive "circles" or maru that protected the castle.

That the suffix -maru is often applied to words representing something that is beloved, and sailors applied this suffix to their ships.

That the term maru is used in divination and represents perfection or completeness, or the ship as a small world of its own.