L10n is short for "localization". This is slightly different from I18n. Where I18n only refers to translating, localization also means changing the content to make it fit a certain locale (country or area). Examples of this are webshops changing the currency to the local currency or sites changing the way phone numbers and values are formatted.
The responsive design glossary explains the many terms used in responsive design and development. It's a practical reference for anyone getting started with responsive design and development.Get an overview of all responsive design terms