Abhidhamma: The science in Buddhism that analyzes the body and mind into smaller and smaller parts. this science helps us to better see that "we" do not have a permanent self/soul.
Dhamma / Dharma: it has range of meanings encompassing "something established or firm". It could refer to universal principle of law, order, harmony, and truth. It acts as the regulatory moral principle of the Universe. It is explained as law of righteousness and equated to truth or 'the-way-things-are. The other translations include ‘cosmic law and order’, ‘duty’, 'conduct', ‘custom’, 'virtues', ‘right way of living’, ‘quality’, ‘model’ amongst others. It is also applied to the teachings of the Buddha.
Dukkha: unsatisfactoriness, discontent, suffering, stress, unease, uncomfortable, unpleasant, difficult, pain, causing pain or sadness, sorrow, distress, grief, misery.
Khandhas / Skandas: Aggregates/Heaps (Physical & mental components of what we perceive as self & of our sensory experience in general