Taking any single definition of what the term reflection is will likely be incomplete and will miss the emergent aspects of the human experience. However, looking at some definitions helps to get started…
1.the act of reflecting or the state of being reflected.
2.an image; representation; counterpart.
3.a fixing of the thoughts on something; careful consideration.
4.a thought occurring in consideration or meditation.
5.an unfavorable remark or observation.
6.the casting of some imputation or reproach.
7.Physics, Optics. a) the return of light, heat, sound, etc., after striking a surface; b) something so reflected, as heat or especially light (Dictionary.com
Based on this group of definitions, the following offers a slightly more accurate definition of reflection as it relates to teaching and learning.
A carefully considered mental representation of some past, current, or future critical instance that comes from a personal - yet shared - experience.
A carefully considered mental representation: From a cognitive standpoint, it all begins with what one recognizes in the mind, and that this mental representation emerges after having a deliberate recollection, regardless whether this representation is clear or vague. From a connectivist lens, this “mental representation” is instead referred to as a recognizable pattern of individual nodes that cognitively form, strengthen, weaken, and lose associations. More accurately, these cognitive connections are black boxed in that the appearance of a single or fixed entity (a single mental representation in this case) instead consists of a more dynamic and fluid (complex) set of associations that remain in continual flux (Latour, 1987). A mental representation might more accurately be referred to as an aggregate set of cognitive and biological nodes that have both diachronic and synchronic attributes. This latter definition is more cogent when considering the social aspects of reflection explained below.
... of some past, current, or future…: Simply one can reflect on past, current, and/or future events.
... critical instance…: A critical instance is some experience that stands out, for better or for worse. It is some experience worth remembering.
... that comes from a personal, yet shared, experience: The shared experience that helps form the mental representation is meant to show perspectival and interpretive variations from individuals sharing a common lived experience. Also, a reflection initially is inherently personal, but should at some point become articulated to others so that the individual can then experience these perspectival and interpretative variations. A feedback loop ensues between the original mental representation and the feedback from others to the degree that either changes to the initial mental representation will result or will reinforce the initial representation, forming stronger associations between nodes.
So, reflection begins as a cognitive process then subsequently leads to a social-cognitive process, connecting the ideational (i.e., ideas, concepts, opinions, beliefs, etc.) with the physical (i.e, materials, objects, technologies, etc.) and the human (i.e., human relationships). Albeit complex, a connectivist viewpoint would simply state that a connection exists between the cognitive, biological, material, and human aspects of the lived experience when recalling personal reflections based on personal observation and interaction.
Latour, B. (1987). Science in action. Cambridge, MA: Harvard University Press.