A cigalike (short for cigarette-like) is an electronic cigarette made to appear and feel around a genuine tobacco cigarette as possible. They're small, light, and mimic all the design top features of real cigarettes, down to the filter pattern and the ash-like LED tip that fires up red when activated.
In the early days of the electronic cigarette, almost all devices on the market were cigalikes. Manufacturers believed the familiar look and feel would make it easier for smokers to switch to electronic cigarettes, and statistics proved these were right. Nowadays, plenty of vapers use more effective e-cig models like the eGo or various mods, but cigalikes continue to be the most used among casual vapers looking for something small and easy to use.
With regards to functionality, cigalikes are no unique of larger e-cigarette models. However, most of them are made up of a cartomizer and a battery, while other, more advanced models have replaced the cartomizer with clearomizers and tanks.
Cigalikes may look almost identical to real cigarettes, but they do have their shortcomings. To be able to cause them to become small and light, manufacturers can only fit them with low capacity batteries than need to be recharged more regularly than the larger eGo, for example. The cartomizers also store way less e-liquid than new-generation cartridges and need to be refilled more frequently, particularly when used by heavy smokers.
Cigalikes are either refillable or disposable and are usually regarded while the entry-level to vaping. Before long, most users move on to larger, more advanced models.