Bias: an unreasoned perspective for or against a person, group, idea, or thing, usually in unfair, prejudiced, or closed-minded ways. Bias may be intentional or unintentional and can show up in obvious (overt) or more subtle (covert) ways.
Systemic oppression: historically-founded and ongoing intentional disadvantage of particular groups based on race, gender, sexuality, ability, class, etc., while advantaging dominant groups (white, male, cis-hetero, wealthy etc.). Systemic oppression occurs through formal systems and institutions (laws, school, health care systems), as well as through social norms, interpersonal interactions, and society in general.
Structural violence: when social structures or institutions prevent particular people (based on age, race, gender, sexuality, occupation etc.) from accessing their basic needs. These limitations are avoidable and typically enforced to hold power over the groups impacted.