Memory or Random Access Memory (RAM) allows your computer to multitask. It temporarily stores data and the higher number of GB (Gigabytes) means more applications can be running in tandem without slowdowns. Some intensive applications for gaming or video editing, require more RAM for optimal performance.
Memory described as 'DDR' stands for 'Double Data Rate' and processes data approximately twice as fast as a standard memory module. When a number appears after DDR (ie DDR3) that type of memory is approximately twice as fast as the previous generation.

The hard drive is where a computer stores all files, pictures, music, and programs. Different from memory which is temporary when in use, storage determines how much data can be saved on the computer. Measured in  Gigabytes (GB) and Terabytes (TB). Terabytes are 1,000 gigabytes.
There are HDD (hard disk) and SSD (solid state) drives. SSDs are faster and use less energy, while HDDs have the ability to store more data and are typically larger in size.

The graphics card (or video card or GPU) displays everything you see and are an essential piece of hardware. It determines the range of color, how sharp images appear, and how well videos or games run without stuttering or pausing. Integrated graphics are built-in to your PC's processor, while dedicated or discrete graphics are separate from the processor and enable you to run smoothly more advanced programs although they typically use more power.

The speed and power of a processor (aka the 'brain' of your computer) determines how well and how fast your computer can do things like create spreadsheets, play games, browse the internet, run software, and more. The more cores a processor has, the better it will be at doing multiple things at once.

The operating system (or OS) manages the computer's programs, files, and devices or its hardware and software. Windows, Android, and Chrome are common operating systems in Lenovo products. The higher the version number, the more recently it was released.