noun

• (countable, uncountable) The act of signing up or registering for something.
• (countable) That which registers or makes something official, e.g. the form or paper that registers.
• (uncountable) Alignment, e.g. of colors or other elements in a printing process.
• (uncountable) The location where guests register, especially with a hotel.
• (music) The art of selecting and combining the stops or registers of an organ.