Both of these terms are related to describing components of an ecosystem, or the community of living organisms that live in a particular environmental system.  Biotic factors are the living components of an ecosystem (biotic meaning biological).  These include living animals, plants, and microscopic organisms like bacteria.

Abiotic factors are the non-living components of an ecosystem.  The prefix "a" means "anti" in this sense, or anti-biological.  Abiotic factors include the soil, air, geographic landforms (mountains, rocks, etc.), and water systems (ocean, river, lake, etc.) that comprise a given ecosystem.  The acronym SWATS is often used here, meaning Soil, Water, Air, Temperature, and Sunlight.

Biotic and abiotic factors both influence each other.  The abiotic factors will determine what kinds of biotic factors will be present.  Particular organisms and plant forms are suited for particular types of environments.  For example, frigid climates will not support lizards and other cold-blooded animals.  Instead, large, blubbery mammals like whales and polar bears are much better suited to this type of environment.  At the same time, the biotic factors will influence the abiotic factors.  Microbes and plant life in a lake will determine what the different factors of the water will be (sunlight levels, acidity, murkiness, etc.).  So both types of factors will influence each other to determine the ecosystem.