SharePoint farm is one or collection of more servers connected through same configuration database. You can configure on one server or you can divide the roles such WFE, APP server, indexing or can define server for specific role.
Single server deployment use only for development or evaluation purpose where we can install everything on one server
2 tier refers to database and Sharepoint server, where we can have one database server to host the SQL server for Sharepoint databases and other server is used for SharePoint.
3 tier refer to WFE, Application server and Database server.
Service applications provides specific functionality to web applications such as User Profile service application (manage user profiles), Search service application, manage Meta data service application, and excel etc. we can associate out desire service application with Sharepoint web application. And each service application contains the proxy which manage the connections to each association or web application.
Web application is upper boundary of implementation, SharePoint central administration allows you to create new web application and IIS will host that web application such as http://portal.eteam.local, one web application can contains many site collections, which runs under same url, on web application level we can define AAM alternate access mappings which enables multiple urls for one application. Each web application have separate application pool in IIS.
Site collection is nothing except the logical container inside the web application, we can define multiple site collection under one web application and we have option to separate content database for each site collection. Each site collection have separate administration and permissions.
There is no hierarchy between sites collections, each of them have separate. Each site collection have its own security boundary
Top level sites and sub sites
When you defines site collection, top level site is created, first site is known as top level and rest of site are created under top level, it will maintain the hierarchy, its built like a tree, you can carry the same permissions known as inherit the permissions or you can break the permission for any site where ever you want.
List and libraries
Under the sites we have list and libraries to save the data, libraries refer to documents and list refer to structured data in form of rows and columns. SharePoint provides many types of lists and libraries such as task list, Announcements, Contacts, Discussion boards, Calendar, Project tasks, Issue tracking and Survey etc.
SharePoint 2013 provide many predefine libraries such as Document library, Asset library, Dashboards library, Data Connections library, Form library, Picture library, Wiki Page Library and Pages Library
SharePoint Configuration Database
SharePoint Configuration database is created while you’re going to configure SharePoint farm, it contains the information such as other Sharepoint databases, IIS Web sites, Web applications, and Trusted or farm based solutions, web parts, and site templates
Default named as SharePoint_Config,
SharePoint Content Databases
All information related to site collection is store in content database, information such as All documents in document libraries, List data, web parts and their customization or properties, user or sand box solutions,