Here are some definitions for terms related to the ancient Indian Subcontinent listed in alpabetical order.
The Aryan Invasion is a theory about Indo-Aryan nomads migrating from the area of modern Iran into the Indus Valley, over-running it and becoming the dominant group.
Ashoka was the third king of the Mauryan Dynasty, ruling from c. 270 B.C. until his death in 232. He was known for his cruelty early on, but also his great acts following his conversion to Buddhism after he waged a bloody war in c. 265.
Most societies have social hierarchies. The caste system of the Indian subcontinent was strictly defined and based on colors that may or may not correlate directly with skin color.
Early, yes, but not very. Unfortunately, although we now have historical data that go back a millennium before the Muslim invasion of India, we don't know as much about ancient India as we do about other ancient civilizations.
Besides the occasional literary and archaeological record, there are historians from antiquity that wrote about ancient India from around the time of Alexander the Great.
The Ganges (or Ganga in Hindi) is a holy river for Hindus located in the plains of northern India and Bangladesh, running from the Himalayas to the Bay of Bengal. Its length is 1,560 miles (2,510 km).
Chandra-Gupta I (r. A.D. 320 - c.330) was the founder of the imperial Gupta Dynasty. The dynasty lasted until the late 6th century (although starting in the 5th century, the Huns started breaking it apart), and produced scientific/mathematical advances.
Harappa is one of the very ancient urban areas of the Indian subcontinent. Its cities were laid out on grids and it built sanitation systems. Part of the Indus-Sarasvati civilization, Harappa was located in what is modern Pakistan.
When 19th century explorers and 20th century archaeologists rediscovered the ancient Indus Valley civilization, the history of the Indian sub-continent had to be rewritten. Many questions remain unanswered. The Indus Valley civilization flourished in the third millennium B.C. and suddenly disappeared, after a millennium.
The Kama Sutra was written in Sanskrit during the Gupta Dynasty (A.D. 280 - 550), attributed to a sage named Vatsyayana, although it was a revision of earlier writing. The Kama Sutra is a manual on the art of love.
The people of the Indian subcontinent used at least four different languages, some with limited purposes. Sanskrit is probably the best known of these and it was used to help show a connection among the Indo-European languages, which also include Latin and English.
Between 1500 and 500 B.C. 16 city-states known as Mahajanapadas emerged in the Indian subcontinent.
The Mauryan Empire, which lasted from c.321 - 185 B.C., unified most of India from east to west. The dynasty ended with an assassination.
Along with Harappa, Mohenjo-Daro ("Mound of the Dead Men") was one of the Bronze Age civilizations of the Indus River Valley from before the time when the Aryan Invasions might have occurred. See Harappan Culture for more on Mohenjo-Daro as well as Harappa.
Porus was the king in the Indian subcontinent whom Alexander the Great defeated with great difficulty in 326 B.C. This is the earliest firm date in the history of India.
The Punjab is a region of India and Pakistan that lies around tributaries of the Indus River: the Beas, Ravi, Sutlej, Chenab, and Jhelum (Greek, Hydaspes) rivers.