Is there a word for the thing that the senses sense?
Stimulus or, more specifically, sensory stimulus.
In physiology, a stimulus (plural stimuli or stimuluses)[1] is a detectable change in the physical or chemical structure of an organism's internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity. Wikipedia https://en.wikipedia.org/wiki/Stimulus_%28physiology%29
The short answer is ‘yes’
The mid twentieth linguistic philosopher used a witty allusion to the novelist, Jane Austen, when he chose, as the title for his book on epistemology
Sense and Sensibilia.
The usual terms used at that time were either sense objects or sense data. This would do fine, if you were not looking for something that would make interesting conversation over the dinner.
You could try the neuter passive participle of the Latin word for to sense:
sensum, which would mean a sensed thing (plural sensa, though you use sensa as we use data, hovering somewhere between singular and plural.).
In fact, much to my surprise, the word sensa does have a history. Merriam-Webster offers it as “Collegiate”, used first in 1864 and meaning “sense datum”
The trouble with that is that before you could use it, you would have to explain it to the guests, and that it would be a risky social gambit. Even in formal academic writing you might need to explain it. The battles over whether we can ever have certain knowledge of the world outside through the senses are at best dormant, people still read or are aware of René Descartes’ thoughts on this subject.
Your question: Eye, ear, tongue, nose and skin are senses. Is there a word for object, sound, flavor, scent, texture in general?
I would call "object, sound, flavor, scent, texture" sensory inputs (or sensory modality inputs). Lots of references, e.g., Wikipedia:
Sensory processing is the process that organizes sensation from one’s own body and the environment, thus making it possible to use the body effectively within the environment. Specifically, it deals with how the brain processes multiple sensory modality inputs, such as proprioception, vision, auditory system, tactile, olfactory, vestibular system, interoception, and taste into usable functional outputs.