The term "relational" comes from the word "relation", which means "relationship" or "connection". In the context of databases and computer science, relational means related tables, where data is structured in the form of rows and columns and can be linked to each other. It may be easier for some to remember the meaning of this term by referring to its English variant, namely - relational (relational database). That is, relation in English means relationship or connection. Thus, the term relational databases / реляційні бази даних becomes maximally clear when you know the translation.

Relational database is a type of database in which data is stored in tables. Each table consists of rows (records) and columns (fields). A key aspect of relational databases is that relationships can be created between different tables based on common fields.

The "Students" table may contain information about students, while the "Courses" table contains information about courses. These two tables can be linked to each other through the "Student ID" or "Course ID" field, allowing for the creation of relationships between students and the courses they are enrolled in.

Thus, relational databases are the foundation of many modern data storage systems, such as MySQL, PostgreSQL, SQLite, Oracle, etc. This post provides a very simplified description of the term, but I hope it gives a basic understanding of the topic.