Books Online describes two mechanisms to ensure integrity and consistency of databases: locking and row versioning. Here is how it defines each one.
SQL SERVER – Introduction to Live Lock – What is Live Lock?
What is Live Lock in SQL Server? How a write request can keep waiting behind a stream of reads, how it differs from a deadlock and how to reduce it.
SQL SERVER – Locking Hints with Correct Scope and Safe Examples
Locking Hints change how a table reference participates in locking. I choose the required consistency before changing the query.
SQL SERVER – Alternate Fix : ERROR 1222 : Lock request time out period exceeded
ERROR 1222: Lock request time out period exceeded. Find the blocking transaction with DMVs, and what to change when you are not allowed to kill it.