TOP TO BOTTOM [C, U] › the distance from the top of something to the bottom: The lake reaches a maximum depth of 292 metres. Dig a hole 10 cm in depth. FRONT TO BACK [C, U] › the distance from the front to the back of something AMOUNT [U] › how much someone knows or feels about something: She was amazed at the depth of his knowledge. in depth › giving all the details: With access to the Internet, students can do their homework in greater depth.